Timothy Cain's YouTube Channel has a bunch of recent videos where Tim discusses various projects he's worked on. There's a clip from a couple of days ago called Fallout Was A B-Tier Project and a new follow-up titled Why I Left Fallout 2. The new clip relates to the prior one, as Interplay's lack of support for Fallout was one issue contributing to Tim's departure from the sequel early in its development. He cites several factors, culminating in conflicts with Brian Fargo over how a bug in Fallout affected bonuses after Tim refused to specify which programmer created it. Here's how Tim came to leave early in development of the sequel:

So when the bonuses came in, he reduced mine, twice. Once he said he didn't agree with me reducing the bonus of one of the people, so he gave that person part of my bonus. But the other reason, the big reason, was he said "You didn't tell me whose bug it was, and you said you wanted responsibility for it, so take it." Big reduction of my bonus for that. And I just looked at him and I was like, "Is this supposed to encourage me, in any way, to work on Fallout 2?" He goes, "Yeah, it encourages you to do better next time." I went home and I drafted my resignation. I sat on it for about two weeks. Came in one morning, told Leonard and Jason, "I'm quitting." Went to Feargus, gave him the resignation letter. I gave them the option: I can leave that day, I can give them two weeks, or I can give them to the end of the month. He chose end of the month. He said I had to go talk to the executive producer. I did, she said "people are going to be pissed." And I was like, "okay, I just cannot do it anymore, it's all in the letter. I'm done."

I go back to my office, I've been away from my office for about two hours. I go back, Leonard and Jason took my letter, copied it, and resigned as well. I can tell you people weren't happy. People on the team weren't happy, Brian wasn't happy, Feargus wasn't happy. But there was just no way I could stay. I got beaten down. All I can tell you is I made an IP from scratch that I always believed in from the very beginning, that no one else had believed in except the team. No one external had believed in until right near the end. And then my reward for that was, more crunch, more responsibility that I didn't want, tons of interference from people who had ignored us for the last three years, and a reduced bonus to 'get me motivated.' I was done. Let me just say this at the end, though. I don't want any of you to change your opinion on Fallout 2 because of this. If you liked Fallout 2, you liked it. The same way I tell people, if you play a game you don't like, just go play something else. If you like Fallout 2, play it. Enjoy it. A really good group of people worked on it. I just couldn't do it anymore. I just couldn't. That's sometimes how development goes. So that's what happened with me and Fallout 2, and that's why I left before it was done.