Much of the real value of degrees to the prospective employee is in added leverage. As long as "enough" employers in field X require degrees, and as long as either a) the unemployment rate in X is low enough or b) your demonstrable skill is high enough, your value is increased by having that degree in X simply because now (non-competes, collusion pacts, and similar practices aside) there is competition for you.
Conversely, if you don't have the degree, your choices for employment are (perhaps unfairly) limited - not just by the employers themselves, but also by immigration policies that limit visas for skilled work to degree-holders. (Of course, if either of those limits were to disappear overnight, universities that have implicitly bet on rising value by rapidly increasing their tuition fees would be in deep, deep trouble, save perhaps those with virtually bottomless endowments. Sort of a speculative bubble, in a way.)
Exactly. One employer unilaterally lowering or eliminating its standards with respect to degrees is not going to do anything in a competitive employment market. What's more, if the labor market becomes a buyer's market for employers, filtering by degree will happen, just because it cuts down the number of applicants.
If you just want to cut down the number of applicants, that's even easier - just pick a random sample to look at.
It only makes sense to do it based on features of the individual candidates if you believe the remaining pool is, on average, better. (... or maybe more precisely, "that you will be able to select better candidates from the remaining pool for a given amount of effort").
No, filtering in the presence of an excessive number of applicants makes sense if the resulting pool is not worse than the original pool. They're saying academic performance is not correlated with professional competence. That means precisely that filtering by degree results in a not worse applicant pool.
Why expend additional effort to filter along meaningless axes to wind up with some unknown lesser number of applicants (which you might then want to shrink further) when you can already filter meaninglessly to end up with precisely the number of applications you want (by simply grabbing randomly and dropping the others on the floor)?
Because it lets people feel better about themselves and is - superficially - justifiable.
A lot of what we do in hiring, even in tech, is effectively just ways to whittle down numbers of applicants, but even here on HN there are people who will insist their way of whittling numbers down improves the applicant pool, because hand-waving and superficial logic.
Conversely, if you don't have the degree, your choices for employment are (perhaps unfairly) limited - not just by the employers themselves, but also by immigration policies that limit visas for skilled work to degree-holders. (Of course, if either of those limits were to disappear overnight, universities that have implicitly bet on rising value by rapidly increasing their tuition fees would be in deep, deep trouble, save perhaps those with virtually bottomless endowments. Sort of a speculative bubble, in a way.)