I can't tell if you are being facetious or not. I hope you are being facetious. I really do.

As many other comments have indicated right here on Hacker News, professional licenses are commonplace for occupations such as plumbers, electricians, doctors, lawyers, and even many types of engineers.

I suppose that central governments (such as the US federal government) should offer licenses for myriad types of software engineers, hardware engineers, software architects, hardware engineers, and so on.

Wouldn't it help companies if they could choose to interview only candidates who were licensed as, say, a level three penetration tester (intermediate penetration tester) or a level five database architect (expert database architect)?

The whole "Let's reinvent the wheel mentality" surrounding software, The Internets, and hardware simultaneously bemuses and frightens me.

"The eye never has enough of seeing, nor the ear its fill of hearing. What has been will be again, what has been done will be done again; there is nothing new under the sun." King Solomon, Ecclesiastes.

and

"I only wish that wisdom were the kind of thing that flowed ... from the vessel that was full to the one that was empty." Plato, Symposium

Why don't we simply allow unqualified, blind, inebriated people to drive automobiles on public roads at whatever speed they would like? Why don't we let a guy who watched a bunch of YouTube videos call himself a brain surgeon, and perform brain surgery on people who don't even need brain surgery in the first place? Hey, wait, i've gotta gureaat idear: y botherr haviing aany ruuules at al! Sheesh.

Without rules, men simply return to a state of nature where life is short, brutish, and mean (Hobbes).

I just found this on Google...

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Origin of Life is Nasty, Brutish, and Short

This expression comes from the author Thomas Hobbes, in his work Leviathan, from the year 1651. He believed that without a central government, there would be no culture, no society, and it would seem like all men were at war with one another.
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The “Wild West” mentality of folks who seem to believe that rugged individualists (not federal agencies such as the US Department of Defense) built Silicon Valley, is perched atop the same type of popular, yet nonsensical, mythology (falsehood) as Horatio Alger's famous character who was actually named Ragged Dick. (Really, Ragged Dick was the character's name, I am not being facetious) who metaphorically pulled himself up by his bootstraps to rise from street urchin to CEO (who was a wealthy industrialist).

Imagine a military, any military, anywhere, anytime in human history, that didn't have ranks, titles, and gasp... tests which members had to pass to move up the ranks. How well do you suppose a military without ranks and without tests would fare in combat? Obviously, such as military would be in a state of hopeless disarray.

Licenses are not a necessary evil; they are a good, and proper way to identify and reward qualified professionals, while simultaneously enabling "the rest of us" to know, for example, who's a mere private, whom we can walk past without batting an eye, and who's a colonel, whom must stop and salute.

Imagine a hiring manager say, "Hey, this kid never went to college, but he's a freshly minted level one software engineer, I say we bring him in for an interview."

Why should every company need to create their own initial screening tests? Imagine a trucking company that needs to hire a truck driver with a particular type of commercial driver's license (CDL). In the employment advertisements they post, such companies almost invariably include verbiage such as, "Class A CDL required" or "Must have a Class B CDL." See? The candidate must have already passed an initial screening test, by acquiring a particular type of license, prior to being granted an interview.

This is obviously a huge benefit to both candidates and companies alike because it saves both sides a lot, and I mean, a lot, a lot, a lot... of time!

These days it is comically inane that tech candidates are normally expected to take an endless stream of initial screening tests to prove their mettle to each and every prospective employer (unless they were referred, famous, or for some other reason exempted from the requirement).

Imagine a CPA (certified public accountant) being required to pass a basic auditing test before he was granted an interview for a new job. Why would a company ask a CPA to take such a test? If a candidate is a CPA, then (unless, for example, he cheated on his CPA test, or suffered some sort of memory loss) he has already proven that he has a substantial amount of knowledge about auditing.

Yes, of course companies should administer their own tests. But professionals licenses can, and do, enable both candidates and companies to avoid the sort of initial screening test which companies commonly require of software engineering candidates. Currently initial screening tests, such as LeetCode, are a response by hiring companies that are typically deluged with a sea of unlicensed (and almost entirely unqualified) candidates, all of whom claim to be qualified.