If Kyle Shanahan son of Mike Shanahan can be successful, why not Schottenheimer.
Probably because Schotty has had very little success in the NFL as an OC, why do you think nobody in the league but Dallas is interviewing him for a HC job? And the dude is in his 50s, he is not some hot up and coming coordinator looking for his first chance. He has been with multiple teams, like the Jets, Seahawks, Jaguars, and the Cowboys and, like I said, he has had very little success. For example, when he was with Jacksonville they finished dead last in the league in passing yards for the season.
As for Kyle Shanny, he has shown that his offense is next level at almost every place he has been, he also is the current HC of the 49ers and has taken them to multiple SBs.
If you cant see a difference between these two, I dont know what to tell you.