I tried finding a job somewhere around this realm. Half the companies were using Go and none of them wanted to talk to me.
just the fact that people practice them before FAANG interviews and their correctness/success rate and speed at completing those tests suddenly gets better by an order or magnitude or more should tell you how little those tests actually filter for any more fundamental abilities.
a proper test for the abilities you mentioned should not only be doable no problem by any working programmer (especially senior and above) walking into that test naked and unprepared, in fact preparing for the test in any reasonable manner before the interview should give no advantage at all.
Complaining about any test obviously just sounds like nothing but proof the test did it's job, to those that want to believe it.
But what you just said stands on it's own and doesn't matter that the probably-lame applicant said it.
If preparing for the test works, then that fact itself exposes the test is not testing what you think, or anything very useful.
I'm talking about programmers working on any kind of application in C/C++ (or other systems languages) with nontrivial performance and memory requirements. It's not like there are a ton of those either, but they're there.
If for some reason some day some market popped up for OS devs that paid better than the other sub-fields those low level programmers are currently working in, nobody need be concerned about supply of programmers who can do the job.