The more money generated the more the cap has to go up. I myself think they should do away with the cap its out dated. It was put in to keep things fair with small market teams vs large markets. Really no such thing anymore. Teams arent even obligated to spend it all. For the most part its just used to justify keeping salaries down. Get rid of it.
they shouldnt be obligated to spend all of it every year. that's the strategy for teams with young players on the rise. For instance, while not on the rise, but more on the downswirl, they have a young team. If they spent every dime of it, they'd never get better. Well, they never will, but still. There is a percentage that the teams must spend, though. This way a young team can acquire a veteran player(s) the next season to be increase their chances of winning.