From a developer's point of view, it seems to me like the dominance of cloud and containers forced the change to devops. Hitherto your org would have a CM team and a separate group of admins/Ops for your deployment infrastructure. Much of it was manually done (follow procedure docs rather than scripting) and software released on a slower cadence.

So at the risk of seeing the past with rose-colored glasses, I'd say things were more straight-forward, less reproducible, slower, and (for developers) simpler.