I don't believe 'subsidised' is the right word in this situation, as the 30bht is not related to the treatment.
My local government hospital doesn't even collect the 30bht, not worth their time I heard someone say.
The hospital get a fixed monthly budget, plus any cash they make from non registered or foreign patients.
And they appear quite keen to get that cash, they don't seem to view it as a 'charity', or making a loss.
My current treatment is mostly X-rays (x2) at 250bht/time, doesn't cost them anything giving 500bht profit per visit.
Doctor already hired, hospital makes 50bht.
X-ray operators already hired, no consumables as all electronic x-rays, shown on the doctors phone/tablet/PC.