I think this is a common fallacy.

To randomly pick an example - sure, automatic filesystem snapshots are a cakewalk these days, and a decade ago they were rather expensive. It seems logical to assume that things that we needed admins to do and rig up somewhat delicate systems for a decade ago are so easy now, we don't need people to focus on that...

This overlooks the fact that the baseline has just moved ahead. Sure you don't need dedicated people for stuff you used to.. but there is new stuff out there that your competitors are hiring dedicated people to work on and push the envelope. if you're okay with doing what you could have done 10 years ago, just using reduced staff, that's great - but it's not going to win you much.