Consider an analogy. We have decided to give the best jobs and highest prestige to accomplished 100-meter sprinters. Track coaches find themselves awash in money, but only if they accept countless students who can barely stagger. With their enhanced incomes at stake, coaches soon find ways to pass even their hopeless students. Special educational stopwatches run slow, giving plodders a chance to sprint to glory.
Steroids become mandatory.
After all, if they flunk too many student sprinters, it will look bad and the kids won't get jobs. Yet employers still prefer applicants who are so certified. This reflects badly on employers' trust in their own judgment. But demanding a degree cuts down on the number of applicants to interview. In the old days, hiring on the basis of race, sex or nationality served the same purpose.