Almost the entire desktop software environment in Linux went 64 bit many years ago. There's just a few edge cases left that use 32 bit, one of them happening to be older games ported over from other platforms (e.g. Windows).
Arm and certain other embedded platforms are of course different, and 32 bit is still common there. In this case though we are talking strictly about PC desktops and servers.
I suspect that what has happened in this case with Cannonical is that there has been a decisions to drop the purely 32 bit version of the desktop version of the distro, something already done with server without any serious problems that I am aware of. There isn't much 32 bit only hardware left around and you can run 32 bit applications on 64 bit just fine, so long as you have the 32 bit libraries.
There has been plenty of notice given that the plan for longer term support of 32 bit legacy applications was through Snap packages, which allow application developers to bundle specific versions of libraries with their applications. Games were explicitly seen as being one major target for this, and it was supposed to be much better for game packagers than relying on standard distro-level versions of libraries.
So far, so good. However, the people involved in implementing the lower level OS side of that decision don't seem to have been very familiar with certain parts of the market, specifically games. They assumed that people using 32 bit libraries only needed older versions of the libraries, not up to date ones and so could freeze the libraries at the 18.04 version. This appears to have been incorrect, and it now seems that at least some game developers (or distributors) need newer versions of at least some libraries.
The solution is rather simple, Canonical just has to continue to package the latest version of 32 libraries and allow games and other niche legacy applications to be packaged with the specific libraries they need. I don't see this as being a big deal, as Canonical would be simply pulling these in from the original sources anyway. Updating them would probably require less work in the long run than freezing them, as it would allow security updates to be maintained more easily.
What likely will happen is that the appropriate Ubuntu people will sit down with their counterparts at places like Steam and find out just what it is the game industry needs and figure out how to accommodate it. I suspect it will involve getting a list of the subset of 32 bit libraries which are actually used and need to be kept updated and then maintaining those.
Wine may be a more difficult problem for those who want to install their Windows apps directly in the desktop rather than sticking them in a container. I'm not sure if there is really a solution there that doesn't involve some sort of Snap package (Snap is a package format that bundles application dependencies together in a cross-distro isolated format rather than in a highly integrated format like Apt).