I partially agree, but how isn't the usual CS curriculum relevant for Sysadmins, DBAs, network engineers and the like?

What CS curriculum doesn't include networks, relational theory, hardware architecture, os architecture? How can anybody in those roles be successful without at least informally understanding the rudiments of big-O notation or without having some light scripting skills?

Certainly CS curricula could be improved, but a good one doesn't do too bad of a job at preparing you for technical roles IMO.