Spike has tried to play it off as if the fighters have nothing to lose. That's not true. The amateurs and semi-pro fighters from previous seasons had nothing to lose. A loss for them wasn't meaningful because their careers are just starting. Tito lost to Guy Mezger and Frank Shamrock before going on a great run with the (disputed) MW title.
The thing with these veteran fighters is that if they lose it could be over for them. Most of them are on the show because they've lost their last two or three fights. If they lose again what incentive does UFC have to keep them around? That's why most of the preliminary fights were hesitant. Wanting to win and not wanting to lose are two different mindsets.
I guess the harder question is how dry is the talent pool going to get if Dana wants to run two or three of these shows a year? They are going to run out of guys like Sanchez and Bisping.