I've absolutely been involved (conducting, coordinating, and receiving) some high value pen tests over the years.
One problem is there is no hard definition of what is considered a "pen test".
I've seen very highly reputable vendors claim essentially out of the box nessus scans as pen tests, automated burpsuite scans as pen tests.
In my own personal definition of a pen test: security practitioners may use those tools amongst others, but they generally leverage them as recon and then try to uncover pathways in from those vulns, in addition to abusing application logic and misconfiguration.
Second problem: paid pen tests have limited scope and time constraints. If the application surface is sufficiently large, that engagement may simply not be big enough to conduct a thorough test.
Contrast this with Bug Bounty hunters (and attackers): they have unbounded time and resources. They can literally keep testing until they find something.. and best part, there are so many of them!
So these public bug disclosures are hard to compare to a private/paid for test.
You could argue, the app owners didn't pay enough for a comprehensive test.. but the downside is: just because you paid more, doesn't mean the pen tester did a better job :(
While they are high noise, I tend to think bug bounty programs are the best fit for the problem space. You end up with much deeper coverage, and a very positive ROI (even factoring in your engineers to triage the bounty reports).