Earlier quoted context omitted.
Yes. Then your most talented citizens will go into other work and the quality provided will go down. This is really quite simple. If there's ways for the most talented to make more money, that's where they're going. The most talented aren't locked into any particular career. Sure, there will be exceptions, but the overall trend will be undeniable.
As long as Hospitals and Law firms continue to hire competent Doctors and Lawyers, this would be a win for society. More people getting health care or access to the legal system, at lower prices, would be a good thing for society. And I don't see any reason why an increase in the number of Doctors or Lawyers would cause Hospitals or Law firms to hire incompetent employees.
So fewer people are going to law school. And this is true even at the top end. The most talented people are going into law in lesser numbers.
It's not a theory, it's actual fact.