For example, in a capitalist economy two people that contribute equal amount of time to work can get different rewards for it. And those who get bigger reward would oppose to changes.
Ironically, free markets are fragile and require government protection to set the playing rules and step away. Usually, the government is not particularly interested in doing that.
(P.S. while the reason for healthcare inefficiencies looks clear enough for me, the case with education is more curious. I think that US education can be a genuine market failure. Compared to healthcare, it is relatively unregulated, and yet people seem to be OK with paying outrageous amounts for something that is not strictly necessary to choose any lucrative career they want. You don't need college education to become a software engineer or quant trader — I've been both without a completed degree, as there are more than enough materials for self-education in these matters these days. There are some exceptions like medicine, but they are that — exceptions).
EDIT:
Here[0] you're actually making the same point as I am. Free markets are fragile. They self-destruct if not externally enforced. Unfortunately, the enforcement itself is not immune to market forces either.
--
To take it to its extreme -- you cannot have a truly free market with existence of the State. However, if you don't have the State, there's nobody to enforce your property rights.