Steve Furber mentions this sort of thing in the interviews I linked to a couple of posts back.
With a modern PC you're generally working quite high up the software stack (or, if you like, many layers of [censored] above what's really going on).
As we know, old BBC Micros and the like are ideal for really learning about the bits and bytes ... not to mention the hardware, architecture etc.
Meanwhile, my own son (already an "Old Bugger", according to a defintion recently given on this forum ... that is, born before 1980 [just]) has just discovered BeebEm
. He'll "get it" one of these days (well, maybe).