How did the end up about the same? Were they paying themselves the same salaries they would have been getting at Microsoft the whole time? Were they living more frugally than they would have been had they been working at Microsoft?
So it wasn't wasted time in that respect, and they'll be bringing in unique and different skills that they probably wouldn't have developed had they been at MS the whole time.
But...there's things like the lower pay they probably had while doing their business, and the intensity of running a failing business is very very hard mentally and physically.
Near the end, one of the guys shut down...hard...now that he's moved on he's recovering. But I think that kind of experience trails along with you for a long while.