Two factors most likely, the first being reputation. And his association with Sean McVay certainly didn't hurt.
The second being that Tepper wanted Reich to build a staff from outside his circle. Part of that was seeing what happened with Matt Rhule but also there was the story of Brian Daboll doing that in New York and succeeding.
Of course, that's not exactly playing out well in year two 😕
Is Bryce the only problem? Obviously not, but as the QB--you know, the most important position in all of team sports--It starts with him. No, not every pass attempt was a jailbreak by the defense. He couldn't do anything even with the snaps where he had some time.