PS:T and the original Fallout are a living proof that the best games are created inside corporate structures, but without too much corporate oversight, when talented people are well-paid, have a lot of time and are given creative control over their work.
I belive it has to be something in between. I know it's not exactly a fan favourite in the Codex*, but Chrono Trigger is a good example. Sakaguchi said that was the first game where he had a very strict schedule and daily meetings, demanding progress reports from everyone. They didn't have "a lot of time" - just under 2 years - which was relatively short for a game like that at the time, and the average for Square's RPGs.
Without a certain pressure, you can get stuff like Daikatana, like Roguey said.
PS:T was a very odd case. I've been reading about development cycles of RPGs for a while, and I've never seen anything like it. MCA worked on it while working on FO2 at the same time. He had a year for himself before actual development began, and when it did, he actually tried to write the whole game on his own. He even mentions the part of the game where he realized it was impossible in an interview, but I don't remember it.
The game as a whole boils down to "What Chris Avellone Had To Say About RPGs", so it's not the kind of execution that can be replicated. No game can be like PS:T and be just as good, because the original is a strong reflection of the author's views on the genre. You could have others go through the same process and create what
they have to say about RPGs, but the result would be very different. Sawyer's Torment, Todd Howard's Torment and so on. That's part of why I believe it's inherently impossible for TTON to be anywhere near as good as the original, but that's a different subject.
The lack of corporate oversight is what allowed it to happen, but it wasn't a laid back development cycle. That first year of notes and concepts cost Interplay nothing. MCA was already on the payroll and he was making another game at the same time. The ~2 years worth of actual production were not a lot, considering the game's scope. Had it been anyone other than Chris leading that game, it would've had a shitload of cut content. It had surprisingly little, considering similar titles. It only worked because the guy is a workhorse and he's a very prolific writer.
As Roguey said, 75% of his content is 300% of other developers, or something like that.
Well-paid is probably a given, but I don't know how much the people in the PS:T team were making. A Kickstarter budget (at least for the time being) wouldn't be enough for 40-50 people to earn above the industry's average, however. PoE had $5+ million for 20-25 and they ran out of money before it shipped.
*One of the best of all time if you ask MCA, however.