Loan forgiveness like other tax incentives merely distort the market. Just pay the doctors what it costs to get them there, we are probably over paying by giving loan forgiveness.
And you think it's justified for others to subsidize the lifestyle of those who live in rural environment?
This is about government funding - it's not a free market solution, it's about the government being honest in how much it is subsidizing different areas. If the total cost was visible perhaps people would say - hey maybe people shouldn't live there.
Sometimes it simply doesn't make economic sense to provide a service that people need.
Witness broadband availability and other things, and you'll see that the free market won't provide a service if it can't make money.