Why Does Physical Therapy Have A Cap?

I would like someone from CMS to answer the title question?  I believe physical therapy is the only discipline that has a financial cap from Medicare. I can not understand the reason behind this decision. Physical therapy is cost effective.  If a senior can not receive physical therapy due to reaching the cap then the patient will seek other alternatives.  The other alternatives could and most likely cost Medicare more money in the end.
Medicare will allow seniors to seek treatment in a hospital outpatient physical therapy center or the ER. What's the difference financially between hospital outpatient physical therapy center vs. outpatient physical therapy center. Nothing, except the bank account of the hospital.  A patient can be treated in ER for physical therapy, what a joke.  No wonder our ER departments are in bad shape.
Our seniors should stay in outpatient physical therapy centers. Where they will receive the best care. We need to develop a better plan than the financial cap.  If Medicare or our government is worry about money then we should develop a outcome plan for continuing services. We should have a range of a flat fee, which increases each year.  After all, there are expenses such as employees, office rent, equipment leases, etc.  There is no reason to have a cap, its not fair to the seniors who need the therapy. If the cap remains then  most likely some other group was rewarded.