Funny, I remember 32 bits being 'the future', now it is the distant past. I think they should keep it all around, and keep it buildable. Though I totally understand the pressure to get rid of it I think having at least one one-size-fits-all OS is a very useful thing to have. You never know what the future will bring.
Just because support would be removed from current and new versions doesn't mean the old code and tarballs are just going to disappear. Can dust off an old 32 bit kernel whenever you want
Always to option to fork it. Linux Legacy? Linux 32? Linux grey beard!
Technologies have lifecycles. Film at 11.
There's always NetBSD. I'm pretty sure that's supporting x86 as far back was 80486 and 32-bit SPARC as far back as... something I wouldn't want to contemplate.