Professionals like medical doctors and lawyers get paid commensurate to their skills. Some medical doctors do not make as much as surgeons do. Likewise, some lawyers do not make as much as others make because of experience, skill level and success rate. Because lawyers can save or make clients so much money, they themselves can charge for those skills. The bottom line is, in America, the free enterprise system, i.e. the marketplace sets the rates for lawyers. That is part of the hard-fought freedoms we in a democracy enjoy. There is only the free market formula.
If a lawyer is lousy, he gets paid nothing or less than other better lawyers. If a lawyer is superb, he can charge more because he is worth it. And a superb lawyer generally wins his or her cases. That is why he or she is paid more on a per hour rate.