What makes you think that colleges put a high priority on choosing the most able/intelligent students for their classes? They have many other priorities (not least, for many of them, picking students who will pay more). Test optional gives them more freedom and even more importantly makes it harder to win the sorts of lawsuits we’ve seen against Harvard, because it’s harder to compare essays than SAT scores.
So why do you think colleges even want to find a “solution”? The move to get rid of test scores was gathering steam even before the pandemic and it just provided the perfect excuse.