I can't say the band wouldn't have survived if this hadn't happened, but after SFaM, I would have to say that the two periods of time when they put out albums that were hits just when they needed them the most were in 2005 with Octavarium, and again in 2011 with A Dramatic Turn of events.
It seems there wasn't that much enthusiasm for Train of Thought, Systematic Chaos and BC&SL, but things picked up again in both 2005 and 2011. I'm not sure about Six Degrees, sales-wise, and I'm also not sure how all of the other albums I've named did in comparison to each other, but the general impression that I get on here (DT Forum) is that if those two albums hadn't been what they were and come along when they did, the band might have suffered severe financial losses, and maybe even have failed completely. same with SHaM, of course.