This isn't really true at all. The fact that the government is a major insurer in the country in no way throws out the rules of supply and demand economics. The reason that reimbursements for procedures and surgeries are so high isn't because someone at the White House picked some numbers out of a hat, it's because there is a cash market for health care in this country that parallels the public and private insurance markets. The reimbursement rates from those markets therefore need to (more or less) match what the cash market is willing to pay or the doctors will go to the cash market and the insurers/politicians lose cusomers/votes.
So why doesn't this apply to Family Medicine? Because at the moment the supply of Family Medicine excedes the demand. Now that might seem crazy: we are clearly a fat, hypertensive, and diabetic nation desperately in need of more primary care. However demand isn't based on what people need, it's based on what people want. If people paid for things that they needed then you could charge thousands for a swift kick in the ass. However demand is instead based on desire, which is why there are multi-billion dollar markets for everything from cigarettes to motorcycles while smoking cessation programs and motorcycle helmets need regulations and government subsidies to sell at all. Honestly the only reason that Family Medicine Doctors are still in business is Medicare. If it were left up to the free market they'd be mostly out on the street, since people aren't willing to pay much of anything to get diseases they don't really know about prevented in some way they don't understand but which involves them doing things/taking pills that immediately decreases their quality of life. Compare that to surgery for a ruptured appendix, which involves a concrete solution for real and current pain, and maybe you'll understand the difference in price points.
To me, the solution to this problem is advertising. There are markets for people who want to invest in their security and improve their quality of life. Huge markets like insurance, self help schemes, and home security sytems. Even nonsensical markets like protective amulets. All of those markets, though, initially needed to create demand through advertising. When your product doesn't do anything immediately entertaining/life affirming you need to sell your customers the idea that they have a need before you can actually sell them a product. Medicine, however, has gotten so divorced from the idea of being an actual product that we've neglected the advertising that generates the fear that sells the service. The trick to raising Family Practicioner pay is not to haggle with the government, it's to convince everyone who tunes in from Adult Swim that they're going to live a horrible fat life and then die a horrible fat death if they don't buy what we're selling. THAT'S how you invest in the future of family practice. And the amazing thing is, it will actually be true.