Quite simply, Harvard didn't come by that $35 billion endowment on the basis of SAT scores alone. Everyone else in that stratus has to compete with that figure as well. This is simply an economic problem, compounded by wealth concentration. Who's going to make a college turn down a potential huge bequest in return for a handful of slightly-less-meritorious admissions? They can admit everyone alphabetically if they want to.
If anyone you know is surprised by this, tell them that you just found out that politicians listen to the people who write the biggest checks instead of the people who have the best ideas! They'll be appalled!