I've mentioned this on HN before, but I have 10+ years experience, a BS in CS from a top 10 school, worked as SWE at Google for over 3 years, I've done 100+ leetcode questions, studied grokking the systems interview/designing data intensive applications, I live in the Bay Area, and I've _still_ failed 90% of my onsites last few years at the top tech companies (Stripe, Lyft, AirBnB, Square, Dropbox, etc).
Reasons for failure vary, you don't get much feedback but when I've gotten it it's been distributed across coding/systems/behavioral.
I've also been rejected at resume round by companies like Instacart and Coinbase.
The interview bar has gotten insanely high it seems. And I left Google way back without anything lined up assuming in this job market I could waltz into a good job with some modest prep but that has not been the case.
I objectively have top credentials, and I find tech interviewing an absolute nightmare. The standards have gone through the roof and one slip up and you get dinged. And the system is way more arbitrary and subjective than anyone admits.
Now, this isn't a woe-is-me story becasue to your point, there's a lot of companies paying top dollar and I have a decently paid job. Furthermore, I'm not failing interviews at random startups but as senior engineer at top companies that would probably offer $400k if they made an offer. They have the right to be extremely picky and subjective, but let's at least admit that they _are_ extremely picky and subjective.
The "I'm a HM and can't hit dev targets", reeks of ignorance as to your own process. I wonder if you do things like tell your interviewers "a false negative is better than a false positive" ? Or let one interviewer use some arbitrary criteria to dock a candidate and then pass on them because of one bad score? Because you probably do lack perspective on how many good devs your company is rejecting if you're only sitting on the HM chair and not seeing what it feels like to go through these rounds as an IC SWE.