What saddens me is the amount of things that are moving so "fast" that they never get any good in-depth books written about them; to stay up to date or learn what's going on you really have to dedicate yourself to keeping up with current development.
Whereas if you want to learn TeX or C you can find amazing books that go into more detail then you'd ever practically want.
I'm fine with it, because the stuff that moves fast is not really designed to be deeply understood by anyone but the devs. It's going to be different in a year, I'm not going to study how some toolchain works.
It's meant to be learned and used as black boxes, and it's all too big to actually study completely, everyone only learns the part that they work on.
I do kind of wish the "moving fast" didn't come with so much "breaking things" though.
Whereas if you want to learn TeX or C you can find amazing books that go into more detail then you'd ever practically want.