I don't have a single data point, and yes- it is antecdotal; but I know many many people with PhDs in chemistry, physics, and engineering. I'm a rarity in my group of friends and work colleagues for not having a PhD.
The engineers all seem to be doing well.
The biology, physics and chemistry graduates mostly get stuck in a loop of post-doc hell. It takes many of them multiple post-docs to finally secure industry positions, and academia is even harder.
My husband is not a new PhD, and my Masters degree is actually newer than his PhD. So our salary comparison is fair. He is also a medicinal chemist, which makes more money than someone with a straight chemistry degree (at least in this area). However, if he had stayed in the Air Force, he'd be making a lot more money than he does since he left. He'd also probably be able to do a lot better if we moved; which we aren't going to do.
On the other hand, the PhDs that do make it to R&D leadership roles (R&D chief research scientist, research director or similar roles) probably turn out to be best compensated employees in an organization
The problem is, while as you pointed out PhDs are relatively rare, these positions are even rarer. There are well more people with PhDs than there are high paying jobs to employ them in. Perhaps, again, my view is slightly distorted because I work in a city with an incredibly high education rate (8% of the
total population has a PhD), but my last company had secretaries with PhDs; many of whom are just hoping to get a foot in the door for when an opening might open up. There are MANY unemployed PhDs in the world, and in the 'hard sciences' too.
Many people with PhDs make a lot of money; but it is NOT a magical key to it. The best way to ensure strong employment opportunities is to be willing to relocate (which the OP seems to not want to do since s/he asked about a specific region).