The inability for a test to have sensitivity at the top end isn’t some fixed property of the universe. It’s just a property of the SAT. Harder tests are possible. The only thing that matters is that candidates know that it’s not at the whim of some human who has decided that 25% Jews is enough or 33% Asians is enough or whatever and that it’s by a fixed scoring rubric.

And then some large number of high scoring candidates will miss out until we have a sufficient number of universities.

Irrespective of the mechanism, it is incredibly racist to use one’s race as a scoring mechanism perhaps by definition.