Is spell dmg worth at high levels?

[Frogreaver]

Another consideration: most of the non damage spell things you can do are concentration. So unless you gosh, you're going to have a fair amount of time spent with a concentration spell up and not all that much you can do that isn't some form of damage.

Casters do area blasting and control better than martials. In return, their default single target damage (unless specially built for) isn't as impressive. 5e is built around preferring more, weaker monsters to fewer, bigger ones.

True, but often if you spend your first turn casting the concentration spell then by the 2nd turn the monsters are mixed in with your allies and not in particularly good fireball formation anymore. Unless you are an evoker or turn 1 fireballing then fireball often loses some of it's luster.