Theirs your answer
The problem is that the UFC can only market certain things. Lightweight fighters do badly on payperview.
At the same time the UFC is doing several things
1 - Consolidating the monopoly they want to build. Right now they are Microsoft in MMA, no challengers. Like Msoft they dont really innovate, they just buy up the rest of the market share and strangle the competition. It is possible for a rival organization to go head to head with them and it will happen. It depends on Japan to a large degree and a few other factors Ill save for another thread.
2 - They OWN champions in every division. At 84 kilod and under they have Anderson Silva, Dan Henderson who is signed to a 3 fight 2 million dollar contract which will be the end of the road for him in the UFC because he lost 2 fights and is now dispensable; and if Anderson Silva ever decides to jump ship or look bad they will bring in their WEC champion to shore up the division or replace who they have. Same for all the other weight classes.
3 - It also is a farm team for the UFC. Beleive me when I tell you who's wearing the belt isn't necessarily the most skilled or the far and away best in comparison to other orgs, Ive trained with Paul?o Filho and frankly he could fight anyone at that weight and win. Other divisions have similiar situations and they want to see who the crowds respond to moreso than who's the best.
Tim Sylvia is an excellent fighter. Minotauro is more exciting. If Tim wins 3 or 4 fights in a boring way, they will find a way to get him out and bring in someone the crowd likes. They can always give that WEC guy a shot, after all, fighting hard for less money and less attention - gonna come in real motivated. In the meanwhile they can groom Brock Lesnar or whoever they want to be the all-American
This is a side note, but I am convinced that the UFC wants the WWE audience. They brought Brock in against a fighter (Frank Mir) tailor-made to beat him, a big heavy and expendenble (after his motorcycle acccident) Jiu Jitsu fighter. Brock is a mosntruos wrestler with little BJJ experience, he was obviously gonna slam Mir and get submitted. All the WWE fans would take note and I guarantee you they will return to see him and his next fight will be someone tailor made to lose against Lesnar while they bring him up and groom him to fight for the title.
WEC is like having high priced insurance with a liquidity policy