true, but i bet you many people would still specialize even if it did not necessarily mean making more money. i say this because not everyone is made to be a GP. being a successful GP requires:
1-the dentist to be at least average at everything and good at atleast a few procedures. this is difficult because some people end up below average in certain areas, which would limit the scope of their practice. i think they call those "hole fillers"...
2-the dentist to be popular. one has to have a very versatile personality that is agreeable to people regardless of sex, ethnicity and class. this is also not easy.
3-the dentist to have a business mentality. this is also a challenge.
specializing basically takes off the pressure in those 3 areas and provides the lucky ones an escape from the possibility of failure. this is off course one way to look at this subject.