If the employer adds more friction with custom, upfront questions, they drastically reduce the quantity of applications while increasing the quality of those left.
If the employer doesn't post to job boards, they reduce the quantity of applications, but they increase those that found them "direct" and likely care more about the company.
It's not perfect, but the biggest issue right now is that both sides are typically trying to put as little effort in as possible.
Debatable. Willingness to put effort into a job application is not necessarily a good proxy for candidate quality. Indeed I would expect that the most desirable candidates can put the least effort in whereas those who are most willing to put up with crap are those with the fewest alternatives. I suppose for certain management structures someone having no better options could be seen as a plus - they'll stick around longer, put up with abuse, probably work for lower pay and less frequent raises - but I feel like they would still do better with appropriately skilled and compensated employees.
If the employer doesn't post to job boards, they reduce the quantity of applications, but they increase those that found them "direct" and likely care more about the company.
It's not perfect, but the biggest issue right now is that both sides are typically trying to put as little effort in as possible.