Keen,
Many of the doctors I know got heterim way back when (so older doctors). I don’t know the details – I know they drive to and from the hospital to shul to daven and then go back if they can.
I am not a posek. I don’t know if there is a reason for the change nowadays (it seems like younger doctors don’t do this). I am just saying that don’t judge someone as being mechalel shabbos because you see them driving.