He also offered to fight GSP at 170 (which Anderson's coaches admitted GSP wanted). How serious do you think Anderson was about offering any of those? The problem with catch weight is it loses casual PPV's (99% of North America is casual at best, given PPV numbers of 1 million out of about 100 million households, so there's way more money in casuals than hardcore MMA fans), and Anderson and GSP both got a nice share of PPV buys. Anderson likes to troll (its part of his charm, he doesn't take things seriously). Offering to change weight (170 or catchweight) is part of his trolling -- if he was serious about his offers to change weight he would have fought GSP at 170 like he offered (GSP wanted that). But weight change was a troll. Ultimately, in no business do you give your competition a free advantage, and changing weight would be accepting a disadvantage for whoever changed weight. Anderson could have made 170 but would have been at a disadvantage. GSP could have made 185, but would have been at a disadvantage. The normal way of handling that is to guarantee more money for whoever agrees to the disadvantage, and both GSP and Anderson are smart guys and would know that, and would have wanted a guaranteed bonus) in the millions for changing weight. The UFC was too cheap to do the normal business thing and give extra for the one taking a disadvantage, neither GSP or Anderson were idiots, and so the fight didn't happen.