Microsoft's plan for future updates is going to be an ever evolving version that you pay a subscription fee to use. Every new update can potentially change the game, but not always for the better.
Any number of updates could prevent games you've been playing for years to stop working because, to move forward, legacy support will be dropped.
DRM and copy write enforcement become more sophisticated and legitimately purchased games that have been abandoned by the developer, or the developer no longer exists may stop working.
All those .mp3s you've been listening to since you downloaded them off Napster, will just disappear.
Maybe your favorite game was just banned due to inappropriate content, do you think you'll be able to play it?
You'll no longer own the operating system, it will be leased from Microsoft. You will be violating their terms of service trying to install these games, so can you complain?
Maybe someday, the government will take over management of our operating system