The only true way to fix this is to set costs centrally.
If you look in thrift stores you can find canes and walkers as well sometimes.
It is just like OTC aspirin, bring in your own bottle to save money as if a nurse gives it to you, you are charged $50 a pill. Buy one for $1 at a Dollar Store and use that.
Since there's a legal limit on profit margins, increasing costs will let them increase revenue elsewhere...earning 8% on $2000 is more interesting than 8% on $1000.
Doctors don't care about the price because they're not paying. You don't care about the price because it's over your deductible. Insurers don't care because they have latitude to raise prices every year. manufacturers don't care because the decision makers don't care.
The French system has a "base price" that they will reinburse for medical supplies/tools. Doctors can go over, but then it's out of pocket for the patient.