I wouldn't do it either (pay 50). But... If I truly thought Teddy was the future (folks keep harping on his 5-0 and saying he's ready), then I'd pick Teddy and let Brees walk like Irsay did Manning. They aren't that confident in Teddy to make that move, so Teddy will walk. It isn't loyalty to Brees, it's that Brees is simply much better than Teddy, even at his age.
If they really wanted to keep them both, they could offer terms to keep them lower than 50 though. Brees could do a Brady and take 20 for one or two years, and they could offer Teddy a long term contract that gives his him a little more the years Brees is there, and give him accelerator clauses similar to what he had last year ( 50% offensive snaps + playoff birth: $2.5M), but with a much higher accelerator. In short, I think the "interest" level in Teddy is exaggerated anyway, and so is his "skill" Doubt he signs for 20, and if he does, doubt he performs. We'll see.