I think I understand what the game "currently" is, and your example of Evolve is precisely what I meant.
Tried it, didn't like it, wasn't going to change so uninstalled it.
Apparently, I wasn't alone since it failed.
If it had a "solid single player experience", maybe (?), it could have been different.
Raiders is also a new experience, multi only, asymmetric PvP, but this time, the lore seems deeper than Evolve, with factions in play, stories behind characters, and so on.
Everything is there to also be a solid solo adventure.
"Why would you want to play the campaign over and over ad nauseum in single player?"
I think here is your perception that is wrong.
I'm not wanting to play in single mode only, but have choice.
If I want to try a new character ? -> solo
If I want to play now and the matchmaking doesn't find anyone ? -> solo
If I'm with a group ? -> multi
If I just want to go easy and look at the environment ? -> solo
That's it.
Not asking to change what it is, but add options so everyone can play with people who actually want to be there, and don't feel forced to it.