Bone on bone means damage has already occurred. Riding without pain would mean much less ongoing damage than riding with pain. Handlebars might do that much. Tendons once torn do not heal. The goal of PT would be to build collateral strength such that the joint could function well in spite of damage. Hopefully to build some muscle that would separate the bone on bone contact.
Shoulders are very complex joints. Think of the range of motion and how many different functions the shoulder performs. The many tendons involved are not that big. Shoulders are less amenable to PT than other joints.
My wife has bilateral biceps tendonesis. She is likely the only person on the planet who has had that done who has full range of motion and no pain. Both times she had surgery there was zero indication of badly compromised bicep tendons until the surgeon was inside. Once the biceps tendon is fully detached it is unlikely it can be reattached and it won’t be reattached well. No biceps muscle means the patient can’t feed, clean, dress themselves. That would have been a bad outcome. Instead we enjoy riding bike together.
Early treatment is always better. If your present doctor is unconcerned it might just be the injury is not all that bad. We will hope.