Even with a 2020 Intel Mac, you're looking at more-or-less 7 years of support from Apple, unless they decide to pull the plug early.
What I said above was a worse case scenario type of thing, and I could be (and likely will be) completely wrong with my predictions about MC not even working at all on M1 Apple Silicon-based Macs with Rosetta 2. Honestly looking at what others have said about Rosetta 2 it's been running most x86_64 apps just fine, so I'll revise my prediction by saying more than likely Media Center will run fine on the Apple Silicon-based Macs. In fact, Bob has said because Media Center already runs on ARM (with MC for Linux) it's possible Media Center can be compiled for ARM for macOS/Apple Silicon (with perhaps some additional changes needed + Xcode stuff).
However...
There's still several unknowns at the moment; 1) what the performance is running on M1 versus the lowest-end to mid-range to even higher-end Intel-based Macs? Will there be any performance issues when running Media Center on M1-based Macs? Or will what Apple says be true and will actually run a little faster? Will MC27's recent Mac improvements with the native screen rendering going to help greatly here? 2) How well video playback is going to work under M1-based Macs? Media Center uses ANGLE which relies on OpenGL ES, which OpenGL has been deprecated in macOS but not yet removed even on M1-based Macs running Big Sur. OpenGL ES 2.0 in ANGLE has a Metal renderer so it's possible that Media Center's ANGLE implementation could be updated (if it's not already updated, of course) to use Metal on macOS. If it is, what's the performance going to like here? What's the performance going to be like using just OpenGL? Would love to see a comparison between OpenGL and Metal using ANGLE, to see if there's any gains. 3) What changes, if any, are needed to get Xcode to compile a working version of Media Center for Mac running on ARM/Apple Silicon? This might be the most tricky part of all, since recent Xcode updates haven't been too kind of Media Center in the last year, causing all sort of issues.
Personally if I was interested in buying one of these new Apple Silicon-based Macs, I'd wait for the second generation (M2) so Apple has time to make improvements and hopefully increase the maximum amount of RAM beyond 16GB (and maybe add 10G networking back to the Mac Mini). There's some tech reviewers who feel like Apple is going to replace these M1-based Macs sooner (like 6 months from now) than later. They've done this before with the first Apple Watch (aka series 0). But we'll see what happens.
So, what Jim said is the best idea and let's be patient and see what happens.