Just because a service exists at some (arbitrarily high) price point doesn't mean society isn't suffering from a shortage of that service.
If Family Doctors could charge $10K/hour, that most certainly does point to a shortage.
His point was, offer Family Doctors $5/hour and see how many family doctors show up, which is 'equivalent' of what is happening now.
Just because a service exists at some (arbitrarily high) price point doesn't mean society isn't suffering from a shortage of that service.