The installations and the near immediacy of seeing a game are the reasons why users choose this system to test their games before installing them.
It was something that could be seen coming, the cloud gaming market is not yet mature enough to be considered a market in its own right. Stadia hasn't fared very well, and other competitors are far behind in this regard. Only Nvidia, Microsoft and Sony can boast of having a solvent product with a catalog and performance that meets expectations.
Although the CMA used this as an argument, the cold data shows that there is still a long way to go before they are real competition for consoles, if ever.
Technical limitations remain the main obstacle
The fact is that during the lawsuit against the FTC, Microsoft provided some interesting documents, in addition to a detailed statement in which they assure something that many of us also suspected, that it is not given the use that Microsoft itself wanted. This may be reflected in the few announcements and how they consistently stopped supporting their game streaming service.
The Redmonds ensure that most users only use the service to test games before deciding whether to install them or not given the ease of doing so that Cloud Gaming offers. However, few play constantly due to the technical limitations that this type of game still has.