Mostly it's because of the guild and habit. Sunk cost fallacy and all.
In my defense, raidlogging twice a week for 3 hours that's practically 90% of the gaming I do nowadays, if not 100%. Of course start of expansion boost of activity, but I fully expect myself be back to raidlogging a two-three weeks after mythic raid is out.
As you have noted in your pretty good post - there is little point to anything in DF anyway the moment M+/raid unlocks. Unless you want them shit colored horse people clothes.