In answer to this question, we could argue that the very nature of the future is to be unpredictable. In our case, however, the answer to this question depends first and foremost on how we define the Metaverse. Some may consider that the Metaverse already exists! Nonetheless, it is still interesting to outline the various arguments that are fuelling debate on this issue:

• Limiting the Metaverse to Meta is extremely simplistic since, in the words of a company representative, it is "a constellation of technologies, an interconnection of systems, without national borders, which needs to be built, operated and governed by several institutions". It is therefore important to pay particular attention to the various initiatives working towards the development of the Metaverse, which is a long-term, iterative project on a global scale, while trying to distinguish the genuine will to develop projects from hype.
• Analysing the positioning of all the players in the Metaverse value chain (see “The Metaverse value chain”) is key to preparing for its development, since "large enterprises such as NVIDIA and Unity are investing heavily to lay the foundational infrastructure, while Roblox, Decentraland, and Sandbox are jockeying to be the preferred portal, and Web3 studios such as Touchcast and TerraZero are working with leading brands to expand their market share”. In addition, although many arguments often confuse the Metaverse with industrial digital twins (see “The Metaverse’s alter egos”), the market for virtual reality and mixed reality headsets needs to be watched carefully, as they are increasingly moving into business markets and generating colossal investments.
• Not thinking that 2022 was the year of the Metaverse, and that 2023 is all about artificial intelligence (AI). In addition to the many observers who believe that more and more companies, including Meta, seem to have “pulled the plug” on the Metaverse in favour of AI, that investment and teams dedicated to the Metaverse in many companies have been reduced, and that the media have turned their backs on the subject, certain statements suggest that the structuring of the Metaverse is underway: "the Horizon Workrooms virtual workspace is a first step towards an office in the Metaverse. And, thanks to the Presence platform (mixed reality, sense of social presence, etc.), new types of applications will be created. [...] We are convinced that the Metaverse is the future of computing and that it must be built around people”.

In particular, the Connect 2023 conference reinforces this argument, since the Meta Quest 3 headset, the development of artificial intelligence, and the connected glasses that have been announced as flagship products for 2024, and which have been presented as "Metaverse technologies", are all about the ongoing hybridization of our daily digital experiences. In other words, the construction of the Metaverse, such as it was presented to Facebook teams in the summer of 2021.

For many commentators, some of the Metaverse’s fundamental building blocks appear difficult to achieve, or even impossible or undesirable because of the resources they would require.

Interoperability raises the question of which devices can be used to experience the Metaverse. In other words, will it be possible to use a headset or other equipment from a specific brand to enter a world produced by another player? It looks like these possibilities are now available, since on 27 September 2023, at the Connect 2023 conference, it was announced that users would be able to connect to and use Microsoft's online gaming solution (Xbox Cloud Gaming) on Meta's latest headset, the Meta Quest 3, as from December 2023.

Furthermore, recent developments mean that Meta Horizon Worlds and Roblox, for example, can be used both on a computer screen and via an immersive headset, reinforcing the interoperability between software solutions and technical devices.

However, when it comes to interoperability between different simulated worlds (i.e. being able to simply move from one world to another with the same avatar and all its features, for example), this seems more problematic.

Many solutions are being explored to meet this need for interoperability. Ready Player Me, for example, aims to create an avatar that is interoperable between several hundred web applications, virtual reality applications, and virtual worlds... However, the solution is limited to reproducing a graphical appearance, and does not allow other attributes (such as an object that plays music) to be transposed and operated from one world to another or from one application to another. Other projects, such as Gravatar and Solid, allow users to store all their data in a centralised and secure way.

Third-party solutions thus seem to be an interesting way of developing this interoperability in the Metaverse, since they could enable the development of libraries describing the properties of an avatar and all its objects. However, this poses a number of technological, aesthetic, functional, or even cost-related challenges.

Another of the Metaverse's promises is to connect an unlimited number of individuals. However, due to technical limitations, it is generally impossible to bring together more than a hundred users (and therefore avatars) in the same digital space (except in the case of special digital environments that require fewer resources). Moreover, the technical limit is not only relative to the number of avatars present in the same digital environment, it is also conditioned by the way in which it is produced: a very detailed digital environment will require more resources than a less detailed environment. It will therefore be able to accommodate a smaller number of avatars than the latter.

Thus, there are not millions of avatars attending the same online event in the same place at the same time. They each attend replicas of the same event, known as instances. The example of rapper Travis Scott's concert in Fortnite is often cited in this respect, since the 12.5 million spectators claimed to have attended were spread across 250,000 replicas of the event. So they weren't all in the same place, at the same time; the start of the concert was staggered to spread the load.

The Metaverse embodies the idea of a network of virtual worlds, a galaxy of digitally simulated and interconnected universes. It's a concept, an ideal. In this respect, it is interesting to draw a distinction between "the abstract concept of the Metaverse 'with a capital M' (as we refer to the Internet 'with a capital letter'), which describes a concept of immersion, [and the] metaverses in lower case. The term metaverse in lower case is used to describe instantiations or implementations of the Metaverse principles. In other words, the Metaverse concept holds within it a multitude of possibilities, services, and spaces, which are open, to a greater or lesser extent, and which will hereafter be referred to as 'metaverses' with a lower-case 'm'” [[[Basdevant A., François C., Ronfard R. (2022), « Mission exploratoire sur les métavers », p. 34: https://www. economie.gouv.fr/files/files/2022/Rapport-interministeriel-metavers.pdf]]]. This distinction is interesting, because the use of the term “metaverse” reflects the reality of today's digital worlds and simulated universes, in all their differences, heterogeneity and plurality.

We can therefore assume that there will not be just one large Metaverse, but rather several metaverses, each constituting a sort of galaxy of worlds governed by large companies, public authorities, and various communities, or even users.

This perspective needs to be taken seriously, at a time when the European Commission, as well as countries such as the United Kingdom and China, among many others, are communicating about projects and strategies linked to the development of their Metaverse; even if these are often “digital” strategies that are closer to industrial digital twins (industrial metaverse) than to the concept of Metaverse that we have just described.