Let's just say I've talked with people who have worked with him on comma.ai and... I heard his cars would be driving into everything if it were just his code running them without all the safety features the folks around him added.
geohot isn't dumb, but he's also extremely good at making himself look like a lone genius, all the while he heavily relies on those around him. This has been a pattern his entire career. He started out pretty clueless and relying on others; these days he's pretty good but still relies on others, and at no point did he learn to humble himself a bit and credit everyone else.
I personally experienced this when we gave a presentation on Sony's PS3 ECDSA screwup, and a week later he posted the root keys obtained using our method. I had to email him to ask him to give us credit since he literally just implemented what we described in our talk, and made no mention of it. Then Sony sued us all (my name was on the lawsuit next to his, even though I had nothing to do with his idea of posting the keys outright).
The reality is "lone geniuses" don't exist. I'm pretty good at what I do (and I also have 15-hour coding marathon live streams on YouTube, FWIW), but to accomplish something great you have to work with others, whether you give them credit or not. The major projects I've worked on aren't "my" projects (even those which I lead/led); they've all been a team effort.