Regardless how good a player is, he can't do anything if he doesn't find a support from the other players in the team. CR7 did quite good in Juve and ManU but look how bad these teams were in these seasons although having good players. Many fans criticised the way CR7 is playing and blamed him for the way the team was performing.
Anyway it would be better for Bayern to find a younger talent. Having CR7 won't guarantee anything imo.
I think better with Bayern Munich to find younger talented than having Cristiano Ronaldo, maybe career from Ronaldo expected about one until two years later, but with young player Bayern Munich have good investment at the future five until six years later. Bayern have chance with profitable if take youngest player because ability to sell if reach top performance, but Cristiano Ronaldo have at the end his career and not any club interested with him after reach golden age on football. But if Bayern want to get more popular awhile is good business take Cristiano Ronaldo from Manchester United although include in several years only.