you can always fire it up yourself and see what its all about. in my experience it generates a lot of code very quickly, that code is probably only ever supposed to be LLM maintained, not by people.
I don't think the op meant Gas Town itself (if they did, my bad), but what has Yegge done with Gas Town? By now it should have released some amazing thing if Gas Town increases productivity so much.
What has Yegge done with Gas Town? Well for one, he has posted a bunch of blog content about it which has generated chatter like this and increased his geek mindshare.
Just because he's operating in the realm of smart nerds doesn't mean he is immune to the value-inverting effects of social media.
(btw I've been wondering the same thing as you and am not sure if there's another answer besides that he and people following his projects keep building projects on their projects: Beads, to Gas Town, to Wasteland, etc.)