If you remove the premium offered by people who just want to scrap the business for parts, and no prospective owners can afford it at your target price, is the business actually worth that much as a going concern?

It sounds to me like your hypothetical doctor might actually be upset that they can't get $2 on the dollar by selling to an unscrupulous party. You could view the PE premium as a way for the good doctor to benefit twice from all the tax benefits that they accrued over the years as incentives to keep their business around.