Testing once the disease is already widespread isn’t all that helpful. You test when the rate is low and that helps you isolate a few cases.
Plus this saliva test isn’t cheap or fast enough for the entire populations at a big college.
Why is it not cheap enough? It costs $4 to create test, and expectation for the general public is it'd be in the $20 range after mark-up. The NBA and Yale have both committed to not making a profit off this test, but rather want it mass produced and rolled out ASAP.
And testing is important widespread or not....nobody wants Covid positive football players in a huddle. Giving a daily test eliminates chance teams will become mass spreaders.