1. He got $100,000 up front, which is enough to help keep the wolves from the door;
2. He gets a percentage of the new guys' concert proceeds, which is undoubtedly a welcome income stream. (It would be interesting to know how Bob's take from the new guys' concerts compares to his take from GBR's concerts).
What about the new guys? Well, it seems that they will have to do an awful lot of touring to earn a decent living and make up for the $100,000. Can they do it? Do they have the chops? The desire? The stamina? Any musician who has been on the road will tell you that it's hard work. Travel and accommodations are not cheap.
Of course, the ones who really got screwed were GBR. All they got from the deal was a pink slip.