What if they interview Brady and his condition for taking the job is canning Loomis?

It's about maximizing what you have, not turning a one-legged Bridgewater into a star.
Bridgewater clearly didn't think that happened and reportedly one of the reasons he went to Carolina was to reunite with Brady:

"As an organization there's things you can do better," Bridgewater said. "I'll just say this, for Joe Brady's growth, that organization, they'll have to practice different things in different ways. One thing we didn't do much of when I was there, we didn't practice two minutes, really. We didn't practice red zone. You walk through the red zone stuff and then Saturday, you come out and practice red zone, but you'd only get like 15 live reps. Guys' reps would be limited."