How many developers selected hardware, configured hardware, burnt it in, racked and cabled it, entered it into a company insurance roster, made and maintained the interfaces and documented it?

This _was_ SA 101 and is the part you ignore. Hell even in 2007 if you didn't know hardware you were unemployable as an SA. What do devs writing json-rpc interfaces to monolith 1212 running oracle X as backend care about infra?

This is the sea change and not everybody agrees with it. You have a 'cloudy' perspective.

I think knowing the hardware is less challenging than previously. The trend is to make everything whitebox and then abstract as software. Hypervisors replace supporting many hardware configurations and software defined SANs replace dedicated appliances.

Configuration, asset management, interface config and documentation are included under things to automate and always have been.

Both your "good" and "bad" examples seem to be more operator-type roles. so much sysadmin work in many shops cannot readily be automated -- doubly so if all of the 'easy' stuff has already been automated!