What do doctors work for?

I was driving home today when I heard some news on the radio. Someone was interviewed about his views on merging of two major kidney dialysis organisations in Singapore, and his reply was that it may need more consideration, as it may make renal medicine less attractive to doctors looking to specialise in a field. After all, if they do merge, renal specialists may end up with only one big employer.

Huh? Does that mean all doctors are looking for is the one who can pay them best? Aren't doctors there with a higher calling, answering to a sense of wanting to help others? Or are most doctors just looking for a way to fill their pockets?

I want to believe that doctors choose to enter their professions because they believe in the calling to help others. Earning a lot of money is just a consequence of their decision to commit to helping others. Helping others, not making money, is the aim. Making money is just a happy side effect. Otherwise, the next time I see a doctor, how can I be sure that he is there trying his best to help me, rather than to pull a quick one to earn more money?