This isn't the same, and Linux/BSD dropped support for 386s because :
1) It's too slow
2) No one is using 386s any more.
486 support will take longer to disappear, because there's still a fair bit of embedded kit using 486 processors. Anything above a Core processor is usable for modern productivity tasks (i.e word processing), although it'll probably chug for the most advert heavy webpages.
However, 486 support only applies to the base OS. A number of packages have assumed at least SSE (P3), and browsers have started enforcing SSE2 (P4). For text only, very slow systems are still manageable. Many X utilities seem to assume Qt these days and I suspect a pentium 4 is the minimum usable platform, I tried with slower and it was a bad idea.
Windows is much more strict with later releases, and running some apps, particularly games, is sometimes tricky. No Man's Sky shipped requiring SSE4.1, which is included in Intel chips from 2007 or later, but not in Phenom 2 chips, the last of which was released in 2011.. That got fixed rapidly.