Its not clear at all because you can simply move the goal post. Someone with 20 years of programming in client side apps struggles with programming a website and can't figure things out on X situation without help. Does that mean they are automatically not professional?

People are experts in different things, but general skills can be applied. My wife notes that there's an effectiveness and mindfulness constant to be applied to "years of experience." There are people in her field who have 20 years of experience, who know less about the regulations and subtle aspects than she has learned in 2.

I bet you can go to most professional drivers and they won't understand the physics at all

Note that I wrote intuitive understanding. It would be highly inaccurate to say they "don't understand it at all." I would question the general understanding of someone who would say that.

My guess is they have, at most, a surface level understanding of driving physics.

Something that someone has practiced over many years in a competitive environment isn't just "surface." This is why educated people should have at least two areas in which they've delved deeply, so they have a firsthand knowledge of what "deeply" means for knowledge.

I would bet that 90% of drivers aren't going to pull out calculus or kinematic equations to analyze a race track.

That's a ridiculous suggestion. Projecting that position on someone is either grasping at straws to make a straw man, or some other form of bias. If a driver knows enough to intuit there might be a way he can improve his line, such that he can seek out another expert's help, then I'd say he could well be a "consummate pro." It's the curiosity, awareness, and drive to peek under the surface which is the difference.

So you base your decision on the few percent of people that can do X vs. the 95% of people that can't, but can solve all other problems without knowing the details?

A more concise way of putting it, is, "Are you smart and informed enough to know what you don't know? Is that sufficient to keep you out of trouble?" The Pareto often rears its ugly head in reality. That last few percent can really, really cost you.

If they do exist, they are most likely consulting

I was an example.

They are being paid more than most businesses can afford

There's an old saying for this: "A fool and his money are soon parted."

They work for companies you probably don't work at

Again, I was once such a consultant. Also, there are coworkers at my current job who are curious, energetic, and smart enough to have such a position, but who don't want one right at the moment.

They are doing research work and publishing papers you probably never read

Nah. Just a modest level of basic curiosity is enough to get you there.

They probably can't solve X problem outside their expertise without assistance

Which is fine, if they're smart enough to know what they don't know, so that they can gracefully navigate their situation.

But the point is that even if abstractions leak, they rarely do.

Boats leak. Could be rarely. Could be a lot. Both can be true of the same boat. It depends on how hard you're pushing that equipment. People can and do make money driving a boat no harder than a dilettante hobbyist. People can and do make money using technology at about that level too. In either case, I just hope everyone knows what they don't know, so no one gets in over their head and drowns.

And that's the whole point of engineering and technological advancement in general, is so that you don't need to know the details.

The point is to get stuff done and to save money while making money. Knowledge is power, but ignorance helps someone else's margins. "You pays your money, and you makes your choice."