I like my NBA salty, and I guess part of Demarcus Cousins' narrative is that he was upset teams weren't offering what he felt he deserved, so he said "screw you all, you won't pay me big money, I'm joining the Warriors for the mid-level."
I'd actually love it if Isaiah did the same. "I'm an All-NBA All-Star who averaged 30ppg, played the day after my sister died, actually played the whole playoffs on a bum hip, put up a monster 53 point game, and ya'll still don't think I'm worth a brinks truck!? You only want to offer me the mid-level? Screw you all, I'm joining the Warriors for the minimum."
Plus it'd be interesting to see how the narrative on him does a 180. From never getting back to his '17 level to suddenly the Warriors signed another automatic All-Star to be their 8th man.