Ubuntu supports 32-bit just fine. I pulled 70% out of my ass and am probably wrong about that (shocker, someone can admit they are wrong and not stubbornly cling to an argument), but most of my Feral purchases stopped working, I had a bunch of Tomb Raider, Bioshock, and some Lego/Sega games all just gone. But the 70% holds when considering that x64 will be dropped too, and by then it will likely be more than 70%. I always seem to just throw all the x86 stuff together when talking about catastrophic loss, because well, the damage being done is still underway.
I really don't want to go through the experience of checking which Steam games are actually 32-bit and which aren't. Even the store page doesn't tell you that. You more likely than not will buy a game that doesn't even work. So that 5600 number is dramatically, and boy do I mean dramatically, smaller than what the official tally is. It's a terrible user experience and I'm done with dealing with that nonsense. I already left for greener pastures.
Ubuntu has mostly dropped official 32-bit support. They do not ship an i386 installer and the OS does not come packaged with 32-bit libraries anymore. Statically linked binaries and self contained binaries will run in 32-bit mode, yes, but the standard repo has no 32-bit libraries
Thanks to the huge amount of feedback this weekend from gamers, Ubuntu Studio, and the WINE community, we will change our plan and build selected 32-bit i386 packages for Ubuntu 19.10 and 20.04 LTS. We will put in place a community process to determine which 32-bit packages are needed to support...
ubuntu.com
I may be wrong but I don't believe the original series of Tomb Raider games ever made it to Mac so I assume you mean the rebooted series. In which case, good news - all the Tomb Raider games Feral ported in the rebooted series work on Big Sur and Monterey. Whether they got updated after you tried them or they were incorrectly listed as 32 bit for a while or something I don't know, but fact is I tried Tomb Raider (2013) as recently as last week. If you do mean the original series however and I'm wrong and they were on Mac - yeah I don't expect that to ever work; Sorry for the loss.
If we go by history, Rosetta 1 was dropped when basically everything anyone ever used ran natively on Intel. I assume the same to hold for Rosetta 2. Most maintained software is already ARM native and we only have a single chip out and Intel Macs are still actively being sold. Games will go because games are not maintained software. They are made, shipped played and archived. It's a shame. But even though I had music on CDs I'm also content with not having a CD drive in my laptop anymore. Or a tape drive... Or a vinyl record spinner attached to the side of my MacBook. - Actually that'd be pretty cool to have as an extension thingy, but never mind that right now.
Actively maintained software running on macOS now will also run on macOS when Rosetta falls. Because the CPU architecture matters very little. Porting from WinForms (or whatever) to AppKit is where the effort lies, not from one CPU architecture to the other. In the majority of cases that'll just work. Legacy Mac software no longer maintained will fall. That sucks if you rely on it. But this is what happens in tech. You also don't run System 7 software anymore, And as time moves on virtualising the necessary environment to run those older titles at good performance also becomes more feasible anyway. You won't expect NES games to run natively on any hardware today, but you can emulate them. For many consoles there's a gap where it's old enough to be unsupported legacy but not old enough to feasibly be emulated. M1 can already run a lot of unsupported games fairly well through Parallels and CrossOver - This is not me saying I think you will be able to easily or even at all play 32-bit games; It's just to say that I don't think this is whole a threat to software archival and it's the natural evolution of technology to leave behind legacy that only slows you down, increases the threat vector and makes the system less maintainable.
The store pages really should tell you when a game *isn't* supported. They just won't always tell the truth about supported titles. If it says it isn't supported, it might work anyway. If it says it is supported though, I've never seen it not work. So you won't wind up buying something non-functional as far as I've seen, though I'll gladly be corrected with an example.
But there are actually quite a few games on there that are listed as 32-bit only that will work (hassle to check I agree. I usually don't bother either. Valve should make Steam able to auto detect the executable rather than relying on manual entries by the dev that don't get updated). Furthermore there are even games that don't have a Mac symbol at all that *still* will work on macOS with official support. In some cases the Mac port was made, officially there for some time, then a license expired so they weren't legally allowed to actively market it, but it's still there and perfectly functional.
Games never have been the greatest strength of a Mac though, and I do have Windows installed through BootCamp on my iMac because of it. macOS for everything other than games, boot Windows for games. - Even games available on macOS will frequently run worse than their Windows counterpart due to less prioritised optimisation.
I'm not trying to convince you of anything. Just having a friendly back and forth
Use whatever system you prefer to use