Conan lost his job because his ratings were low, and in TV, ratings are everything. So the equivalent would be if Rodgers had played badly after taking over for Favre, and then Favre came back to replace him. It would've been a little weird, but understandable. Thankfully it never came to that.
TBS is a much better place for Conan, anyway. His audience is loyal and knows where to find him, and he can be a little edgier again.