They can only have 11 players on the field at once. Just like every team. Yes they keep signing players but they can still only line up 11.
Catch and release. WRs want to play on the Pats because they make passes. If they can afford to hire a lot at low value they can make them all compete during training and preseason. Cut what you don't like and force them to try to get spots on other teams and not have the benefit of training camp with that team. Screws with all FA and teams.