A supplier can take a prescription by fax, portal or email without much difficulty. The problem starts the moment that order enters the system that actually fulfills and bills it. From that point the referring clinic is blind. They do not know whether documentation was sufficient, whether authorization is pending, whether the order shipped, or whether it was rejected three days ago and nobody told them.
So they call. And because they call, supplier staff spend their week reading order status down a phone line instead of processing referrals. Clinic staff spend theirs chasing. The patient — who is often waiting on equipment they need immediately — waits longer than anyone intended, and nobody in the chain can say why.
The reason this persists is not that suppliers are unaware of it. It is that closing the loop means integrating a provider-facing portal with a billing and order management system that was never designed to be read from the outside, over a connection that has to satisfy the security expectations of both parties. That is an engineering problem, and it is the reason most suppliers still run this on phone calls.