I think the concern is more about the theatre of most modern pen-testing rather than expecting deep bug-bounty work. I'm not a security expert either, but I've had to refute "security expert" consultations from pen-test companies, and the reports are absolutely asinine half the time and filled with so many false positives due to very weak signature matching that they're more or less useless and give a false sense of security.

For example, dealing with a "legal threat" situation with the product I work on because a client got hit by ransomware and they blame our product because "we just got a security assessment saying everything was fine, and your product is the only other thing on the servers" -- checked the report, basically it just runs some extremely basic port checks/windows config checks that haven't been relevant for years and didn't even apply to the Windows versions they had, and in the end the actual attack came from someone in their company opening a malicious email and having a .txt file with passwords.

I don't doubt there are proper security firms out there, but I rarely encounter them.