Not a normal human
There's also the fact that while Yahtzee makes mostly negative videos, he himself didn't become a miserable pile of shit if the fact he got married and had a kid is any indication to go by. Between that and his old Let's Drown Out videos with Gabe, I get the impression that Yahtzee at least has a healthy social life, unlike Jim who only has a social life on Twitter. Yahtzee may be negative, but he's not miserable and depressing to watch. Jim on the other hand exudes this ugly and sad presence in his videos; he looks like someone who hates where he is right now and that makes his videos less appealing. Not to mention, Yahtzee's done a better job branching out with actual books and a couple of new series on The Escapist which means he can actively challenge himself doing new things. Even if people didn't watch Yahtzee's other stuff, it's still good for him on a creative level. Jim hasn't branched out in any capacity in a long time, and you can see how that's detrimental to the Jimquisition when it's literally the same thing every week and even regular viewers are getting sick of it. Jim's in a creative rut and the steps he's taking to rectify his declining viewership do nothing to help his actual problems.I think Yahtzee is the best example that not only can you make a career out of being a negative cunt, you can do it while only putting out one video a week. The difference between him and Jim is the former clearly still has a passion for writing (even when he hates the games he's writing about,) so his material remains fresh and funny even after 10+ years.
The Jimquisition, on the other hand, has reached the point of parody where you don't even need to watch anymore to know what Jim is going to be talking about, and I think that's why a formula change-up (which is a good idea) still wouldn't save Jim's channel because instead of one video of a miserable cunt being miserable we'd get them daily.