Just because you don't see fhwm, doesn't mean they don't have them or need them. I would bet your state/county requires electricians to have a license, and your mechanic is likely ASE certified.
The guy who came out to install a generator is licensed, and he needed one for the inspection, but that's an exception not the rule. The claim was that all you need is the skill to make a living, and around here that's demonstrated daily. Sometimes they don't even have the tools and use mine. Frequently they require cash, and that's standard procedure here.
Place I live in Europe, it would also be outright illegal. Biggest city or rural, folks here respect their local communities and only get official pros for any serious work.
I could literally rebuild it 3x for the all the bullshit insurance and regulatory costs were it I got inspections, licensing, and insurance.
They've been brainwashed into "safety" since they were 3 years old, so anything outside of that box is literally unthinkable to them. Their mind literally shuts down trying to process it.
So it's workable for a niche group of people but not the majority.
I also got my land incredibly cheaply that way. No one wanted to take a risk on an unproven plot of land, everybody wants some place where they can already legally get water/power/electric. By doing all the legwork and legal to prove utilities I basically made $30k profit in a year just by passively testing and connecting water/electric/septic at my own risk.
I built this place for ~1/3 the price of anything else available because even a completely burnt out husk of a trailer is more expensive than DIY building a house due to the weird dynamics of the housing market that places a gigantic premium on being the guy who takes all the risk of connecting utilities and getting a permitted residential structure.
Your thesis that I can't sell an actual house for the price of all the unmortgagable burned out trailers that sell like hotcakes is interesting but false. I don't expect this dynamic to change much until most of those ~0% mortgages expire or a massive new supply of housing emerges.
And then you have companies like my old one-- they didn't have a fire protection license, so they hired an old dude to come in once a year for $40k and borrowed his so they can now do sprinkler and standpipe work legally. It's the same idea everywhere, except more fraud is involved in the cities.
Ok so in your small rural town, where people take up trades because they’re struggling to make ends meet, and where you have to settle for whoever is available, and where if someone screws you over word of mouth on its own is enough of a deterrent and is easily enforced, you can get by without relying on licenses. As far as giving general advice to young people, the original point still stands that you generally need to jump through some additional hoops to make a living off of many of the trades. Yes there are exceptions but most young people aren’t looking for answers that require you move out to the boonies and where you’re going to be scraping by.
No, it might only be an exception that the person didn't break the law and got the inspection. Pretty much any electrical work that would require an electrician requires an inspection by code.
Just because some of the people around you aren't following the law doesn't mean that you can really make a living that way. All it takes is one mistake and you get wiped out because you didn't have insurance and were operating illegally. I've lived in rural areas and people doing stuff as a business without the proper permits is the exception.
People who trade this way with one another aren't going to want to wipe the other guy out because it is mutually assured destruction.