> It's extremely difficult to find, hire, and then put into the right position a competent security engineer
I disagree. There are quite a few talented security engineers out there that aren't employed. For some of them it's because they don't have impressive resumes or don't market themselves as such; let's assume that's on them.
But the other reason there's not enough security engineers is companies don't consider security essential. I have worked at some big companies. All of them failed to implement basic security best practices. If there were any red teamers on staff, they only focused on one or two areas of the company. The reason is simple: paying for security doesn't generate revenue or increase your stock price. So business leaders don't care if it's insecure, so hiring managers don't hire security engineers.
More generally, the vast majority of companies consider IT to be a cost center which means cutting costs (and the corners along with them) and going with the cheapest bidder is just Standard Business Practice(TM).
Of course, this means the security is going to be a shit-show and there is financial incentive to delay improving things for as long as possible; the recent discussions about "cyber-attack insurance" in response to the attack against retailer fridges sort of epitomises the problem: even when the nightmare scenario happens the suits refuse to see that the root cause of the problem was the application of Standard Business Practices(TM).
Yeah, the problem isn't a dearth of technical security expertise, the problem is turning that technical expertise into meaningful organizational changes, which requires a rather different skillset (as far as I can tell: people-skills and managing/navigating bureaucracy). And, further, getting anything done is going to be a constant uphill battle in most organizations because, as you point out, paying for security doesn't [directly] contribute to quarterly revenue targets, and even worse, often times puts you in direct opposition with the people who do contribute [directly] to those targets.