From personal anecdote I find that it's just poor culture which prevents qualified people from getting hired. Even with tons of reqs open, no one new as added to the staff.
Yes, they should. The vast majority of QA should be automated unit and integration tests.
> QA is unnecessary
This is objectively false. Even if you perform 99.999% of all QA in an automated way, you're still going to miss those edge cases, like the infamous daily kernel panics due to buggy support for external USB-c displays that only real humans testing your product in the real world with 3rd-party devices can find. QA is still extremely important, and when companies like Apple neglect it, they end up shipping buggy and disappointing products.