Arguably it still hasn't matured yet. Or at least it's nowhere near to be a solved problem and we'll probably sidestep it before ever coming up with a real solution.

I'd put it in the same bucket as TODO lists. After centuries we're still not set.

Depends on the printer. I still remember the LaserJet 4000 series with great fondness. They were absolute tanks that almost never broke. You did have to replace wear items like rollers, but that was it.