My intuition is that for hemophilia this is not as much of an issue. This is because most patients get their care — or at least make decisions about which factor products to use — at hemophilia treatment centers (HTCs). HTCs are part of research hospitals, and the choice of drugs to use is typically made with a salaried staff physician with no direct financial incentive in prescribing one drug over another. Which is probably a different scenario from when choices like this are made in private practices.
That said, the risk is still there while newer factor products get produced and marketed. Physicians and patients want better results and so there’s no reason in principle that disingenuous marketing could lead to using newer, more expensive but not better drugs. (As I noted, we switched, and the drug was truly more effective. Other people’s positive experiences factored — pun! — into our choice.)
However, HTC physicians and patients I think are cautious about changing drugs willy-nilly out of fear of adverse reactions such as inhibitors. In our case — and this is standard practice, when we made the switch, we took labs to test the efficacy of the new drug.