Earlier quoted context omitted.
I don't understand the question. Maintenance will always be a thing, carried out by humans, cron, or the os itself doesn't really matter.
Why doesn't MS Windows do the maintenance - CCleaner does things like clean up ancient cache files, remove Windows update files, remove registry entries for software that's no longer installed. That sort of maintenance seems like it's the result of poor design in an OS that has the hood welded shut. I actually used ccleaner on Win 10 recently, an MS update had associated loads of files with TWINUI which wasn't instal…
Plenty of examples of native apps doing something that third-party apps do much better.