I'm more inclined that PE certification, like so many professional certifications, is mostly about eliminating competition and running a kind of cartel,
I can assure you that the PE certification process/requirements was started with a good intention of preventing disasters. However, the ONLY thing that prevents disaster are people who can actually do the work properly, and that the certification process/requirements are incapable of making sure that critical calculations are done correctly. We only can certify that they should be done correctly, and the person doing them should be able to complete those calculations correctly. Not that they actually can or will.
The REAL test is, if a government requires certification, and is in charge of certifications, then the liability for any failure by a certified "engineer" should rest with the certifying authority, or the certification is meaningless. And now, you know where the real problem is. It isn't the certification or the process, it is there is no liability on/for people making the requirements up.