The first part of your statement is pretty worthless, as comparing the perennial loser Bucs to the Patriots is silly. The second part....they still could have let Mankins go this year or trade him this year....so, the space cleared was wasted. Let us not forget that the Patriots and Brady really could have used Mankins last year. They won the superbowl and the guys came together, but it had some rough patches for sure.
Mankins tends to play injured a lot, it is his nature...you know, play a whole season on a torn ACL and then get killed by fans like you because he let Brady get hit a few times....meh.