Uh, well, the problem was solved centuries before Rand took it up. St. Thomas, for one, has a bit to say about economics.
It's like saying "Gilligan's Island's Timeless Moral is Getting Off The Island." (When we all know the timeless moral of Gilligan's Island is that any red-blooded man would take Ginger or Maryanne.
Uh, in what way was "the problem solved?" Define the problem and then the solution, if you can.
I believe Thomas Aquinas considered profit to be morally neutral with any virtue or vice coming from what a person did with his profits. Rand however considered the very act of making a profit virtue.