I’ve seen this happen plenty enough even in SV. If someone wants you fired - they’ll do it asap.
So even if it surfaced the best candidates, hiring anyone that applied and then firing 90% of them after a week would result in a depressing work environment and an ever shrinking pool of qualified candidates (who wants to upend their life to take a job they only have a 10% chance of keeping?). Not to mention the cost of onboarding.
This is how we get to the status quo: do as much filtering as you can before you hire.
Slacking off during the hiring process with the intention of firing a large portion of the people you hire is a violation of the social contract and a huge asshole move.
HR is really only qualified to filter out based on the qualifications on paper. These are sometimes misleading and occasionally outright fabrications. Those can really only be verified by someone with the appropriate technical skill to separate bullshit from an accurate representation of the abilities of the candidate.
If the hiring manager wants the firehose of the "everyone who clicked quick apply" on LinkedIn or Indeed, then fair 'nuff. However, my reading of the comment that I replied to was the issue that HR wasn't filtering out unqualified applicants. Removing HR from the hiring process won't improve on that issue.
There's a couple of "problems with this idea in reality" I feel I should point out:
IMHO the real problem is HR: They suck at filtering out IT candidates. They're so bad that you'd be better off throwing darts and sending those resumes off to the hiring managers. They filter out perfectly qualified candidates that could be the best thing that ever happened to your organization and then they let through people who's only useful skill in life seems to be making a good-looking resume.