It's somewhat similar to the reason people (like me) restore and drive old cars, also despite the "noise and power consumption" (and some happen to like the former ;-) --- they're relatively simple and well-understood.
Likewise, there is also a very active retrocomputing community, although a lot of it goes back much older than 486 or even PC --- the C64, ZX, and the like continue to have plenty of new software written for them.
[1] and if you ask for a datasheet or any more details about it on their "excellent community" (to quote some), you basically get told politely to f'off: https://www.raspberrypi.org/forums/viewtopic.php?t=163420