It is foolish to think that the Pats won't be seriously hurt by the lack of talent at WR if we don't bring Branch back. Decent success in two preseason games doesn't show anything -- it's a simple fact that our offense would be much better off with Branch than without him.
If Branch holds out into the season, there's always the possibility that the team will look good on D and running the ball, but struggle in the passing game -- we all seem to assume BB would hold firm on principle, but I'm not so sure. If this looks like an otherwise SB contending team w/ a big whole at WR, I'm not sure he wouldn't be willing sweeten the pot to prevent wasting a potential championship season. Call me crazy.
Even if the Pats do ok w/out Branch, there's still the fact that he'd have to worry about getting injured in only 6 possible games, instead of 16 -- and not even those, if BB suspends him. In the offseason he would either be let walk, or franchised and dealt -- with Branch being able to scuttle any deal he didn't like by intimating to potential suitors that he would be hard to get under contract.
Also, his agent would advance him the money for the fines, to be recouped when he gets Branch his big payday, so I don't think finances will have that much to do with it.