Knowing "a good plumber" is no longer knowing a genuinely skilled plumber. It's knowing a person you have an affection towards, one that has been marketed well to you.

Perhaps I am naïve but I believe that in the past people were more discerning about the true skill of an individual and less clouded by the appeal of the individual.

Yes, you are naive, and I don't mean that as an insult, but as characterizing what, IMO, is a flawed interpretation of how human interactions and assessment work.

How do you judge a skilled plumber? Some might judge that person on speed. Others might judge it on cost efficiency in fixing the specified task. And others might judge it on the ability to anticipate other problems in the system and provide reliable estimates and options.

What I might consider the best plumber is different than what...the Plumbers Society would consider it. But a friend whom I trust may have the same standards as I do, and in that case, the hired plumber benefits from knowing my friend. Despite the many, many instances of when this has led to cronyism, is that such a wrong way inherently for business to be conducted?

You have reduced the discussion to what, subjectively, makes a good plumber.

I will try to bring this back to my original point - One that is not necessarily a good marketeer may be far more suitable for the job, yet good marketeers but unskilled plumbers (to say unsuitable for the skilled job at hand) seem to be "successful" in terms of success and profit in their field.

So how are you quantifying this? The metric that you've set up: skill level vs. popularity/success, is not easy to measure. Because for the most part, the examples that will easily come to mind of good and bad people will also be the popular ones...

So when you go into this with the expectation that success/popularity should be directly related to skill, you are going to naturally remember the many examples of when bad people somehow have success. And so you conclude: success is not correlated enough to popularity, or else Person XYZ would not be famous/rich.

But let's say I, on the other hand, think there's a strong correlation between success and skill...and I can think of lots of successful people who also happen to be skillful...but I suffer from the same confirmation bias as you do.

So who's right here? I don't know, but I'm just pointing out that your assertion may not fit the actual facts (if we could ever quantify it).

My bias is towards there being a lack of connection between ones marketability and their skill based on my biased and limited observing of people performing roles they are believed (by people who put them there) to be better at than it is revealed that they are.

I have also observed people keeping these roles through the relationships they manage with the people they are accountable to. Relationships in these circumstances are about marketing one individual to another.

I'd be surprised if these observations are limited to my own experience. Somewhere in amongst all the biases of our individual experiences we must determine something to be fact. For if I read and agree with a scientific paper which outlines something I regard as fact, it is still subject to my experience and hence we must ground ourselves on the basis of our collective experiences aligning.