Shortest way I can sum it up is mid-life crisis upon realising he has no prospects except doing the Jimquisition for the rest of his working life.
This also explains his pivot towards wrestling, despite rapidly approaching the age most pro wrestlers would be retiring/moving into acting.
I actually think the opposite is true: Even if Jim had kept his fashy look from peak JQ days he'd still be bleeding subs. His current look distracts from the fact his content has become utterly insufferable and aggressively repetitive; not to mention he's massively reduced his output from multiple videos a week to 1.
TL;DR It doesn't matter if you're a gross genderblob or Gigachad, nobody is interested in hearing the same 3 or 4 topics covered verbatim, once a week.