The high wages of the plumber are naturally a function of supply and demand. They are often in part a result of a dearth or even a complete absence of competition.

If there were an overabundance of available skilled plumbers in every community, the wages might drop.

Needless to say, in any given US community there is often a shortage of available skilled plumbers but rarely a shortage of young people with college degrees.

PayPal, Thiel's claim to fame, had one competitor: X.com. And they merged.

This is a fair point -- if vocational school were more widely promoted, there would be more people with vocational training and the wages would go down. However, I still think it would settle into a reasonable level of compensation, and regardless, there will always be a base level of demand to be met as long as we keep using electricity and indoor plumbing.

What I find interesting in your anecdote is the son chose to attend university and develop his talent as an athlete before starting full-time work as a plumber.

Even though the university experience might not have a monetary "return on investment", he chose to pursue it.

Now, it's also worth noting he's on scholarship. Whether that was the deciding factor in his choice to attend we cannot be sure just from what you've told us.

But nontheless he is investing his time at the university when he could be doing plumbing jobs and making money (or, by analogy, working on a startup that a certain VC has an interest in).

You mean like playing on people's fears of paywalling by saying something like

"If we don't alllow web advertising to be unregulated, all good content will be paywalled."

You mean that kind of irrational fearmongering?

Not only social pressure, but perhaps legal pressure too.

"you are expressing your desire to not be tracked."

Yes. And I think this is important. For example, for cases brought by the FTC, class actions, and other litigation it might be useful.

If a company ignores the Header sent by the user and tracks her anyway, then one could argue the company too has expressed an intent.

The Header is machine readable like any other. A server can parse it and take a specific action based on its presence or absence. Arguably it does have technical merit.

"No, there's no evidence to support my worry."

OK, thanks.