All this is true, but I'm sure they have backup plans. They have two quality PGs behind him in Diarra and Nowell, and Hurley has talked about Ross possibly being able to play point. Mahaney's difficulties are baffling, but he has time to learn how to fit in better and fill a role. I don't see him as a backup shooting guard, that may be his personal strength but the team doesn't get better with him pushing Ball/Stewart/McNeeley/Ross to the bench. He has to succeed as a PG or he doesn't have a role.
He's not the only one who has to grow, other guys on the team do too. Solo Ball's every shot was a 3 pointer, and had 0 rebounds, 1 assist, and 5 fouls. Ross had 0 points and 0 rebounds. Between the two of them they played 39 minutes. The whole guard group has to get better.