Here is a clip about the construction trades program in the Pasco, WA School District (my alma mater, class of 1969).  I'm not promoting the public school system, but it is good to see job skills training being provided to young men.  Vocational education is now sometimes called Career and Technical Education (CTE), and is slowly overcoming the misguided stigma that its for people not smart enough for university.
https://www.applevalleynewsnow.com/news/pasco-high-school-students-build-524-000-home-launch-construction-careers/article_32a91b8d-e254-49fd-9eef-0abc9c0fad06.html?fbclid=IwY2xjawKlhJhleHRuA2FlbQIxMQBicmlkETFtdWlGTmpHcUU5WjdjUlVCAR46lJ58ZJwS9QEvIZleBEcGwAbV0bTu4kMh6oQ_CybXtw3gKFv_x_nyJ14t8Q_aem_MIrmNhQgOqOV_pdodOjL_Q

Last winter quarter I took a welding class at my local community college for a refresher.  I've not had that training since high school farm shop, and I hadn't picked up a stinger in over twenty-five years.  I wouldn't have known what amperage to set or what rod to use for a particular application.  The young man in the booth next to me was finishing the third year of a five year electricians apprentice program.  Welding wasn't part of being an electricians apprentice, but they are encouraged to broaden their skills set.  He had to pay his tuition and lab fees up front, but if he passes the welding classes his union will reimburse those.  He also said that in 2024 he made over $100,000 (at age 22 or 23), albeit a lot of overtime was involved.

The skilled crafts ... mechanics, welders, electricians, plumbers, carpenters, machinists, masons (as in stone work), etc. ... will always be needed, will always be in demand, the work can't be exported nor done online, and these jobs are typically better paying than occupations in the hospitality, retail, and service sectors.  They are also useful skills to enable one to work their way through university.  It would be great to have buildings designed by architects who had once worked construction, or to have a vehicle designed by an engineer who had once actually worked on cars.

I was reluctant to bump my own post, but I had also been hoping that others might provided examples of good careers for a man to support a family.

There are frequently posts about the difficulty a young man may have in establishing a domicile and having sufficient income to support a family, in addition to finding a suitable wife to begin with.  Yet, I gave an example in the OP of a guy in his very early 20's with a six figure income, though he is still an apprentice.  These opportunities are widely available today.  I posted a video about young men learning house building while in high school.  Even if they don't ultimately go into the building trades they are learning skills that will serve them well in life.

A guy I went to college with (I graduated in 1973 with a degree in animal science with an emphasis in dairy production) received a parcel of land (1/4 - 1/2 acre maybe) from his family when he married.  After work he built a studio apartment type space (open floor plan, murphy bed, room for a baby crib and a small child's bed,  kitchenette, enclosed lavatory and shower, an attached utility room with laundry facilities and storage.  It was part of an overall plan and designed for expansion.  Over time, as his family grew, he added on bedrooms and living space.  The original "studio" was designated to become the garage, but he decided it was too nice for that, so it became a family room and he built a shop building for the garage.  This was done at a much lower cost that a contractor built house, and it was mostly a "pay-as-you-go" project, so much lower finance costs.

In 2022 a good friend of mine's son got married, in a Solemn (not High, Solemn, with deacon and subdeacon) Mass at the diocesan parish of St. Patrick's in Walla Walla, WA.  The family has a farm and winery where John works with his family.  To save money they have been living in a camper on the farm, with a roughed in larger kitchen in one corner of the winery.  Their second son was just born in the past month.  In the interlude between cherry harvest (happening now) and apples and wine grapes later, John is going to start building a house.  This will be constructed in segments and "pay-as-you-go".  John also wants cows, including a milk cow, so I'm going to see if I can get the Surge portable milker I used in high school going again (the blessing and curse of a farm is that nothing gets thrown away).

For sure, these two couples had some advantages.  They both had free or low cost land available and could tap into already dug water wells.  The first guy's family is in the logging road construction business and the 2nd is on a farm, so there is access to trucks, tractors, trailers, and other equipment and tools.  Both are from large families, extra help can be called in when needed.  I've known other couples who built kit houses at a lower cost than purchasing an existing house.

Young men should be looking into the skilled trades for training and work opportunities.  Apprenticeships are often available without cost through union halls, plus one is working and has income during training.  Training programs, often through local community colleges, are lower cost than traditional four year university degrees.  Even if one is home schooled, in some states they may still be able to tap into the local secondary public school CTE programs.

No, but they can (and often do) import laborers from Mexico ... to bring wages down.

I believe that these are the two most solid bets ...

1) healthcare (though there will be some dropoff after the boomers pass away)

2) auto service -- given how complex autos are becoming, more and more they say that these jobs are half IT and half mechanical skill, just as cars are becoming half computer, half mechanical, and it'll only get more that way if they move to electric vehicles.  Typically workers from Mexico would not have the technical skill and the communication skills required to hold down these jobs

Everything else is getting more and more thinned out.

Yes, but that "ivory tower macroeconomics take" is contradicted by the reality on-the-ground, at least in my area.

There is plenty of such work to go around, and the prices for such labor are not low at all. Yes, Mexicans are willing to work, and to do "real" work at that. But there is a shortage of such workers; it doesn't matter if there are 100,000 workers, if there are 200,000 workers' worth of jobs to be done.
On my property, there are so many things we need fixed/done around here, but we don't fix them because we don't have a handyman available. I think there is more work to be done vs. the number of people ready & willing to do the work.

I live in Texas, where there are PLENTY of Mexicans. Based on what I've paid out for various jobs in the past 5 or 10 years, I'd say prices haven't been driven down too far yet! Even the Mexicans are making pretty good money.

So yeah, there is money to be made for anyone willing to work. Anyone willing to break a sweat, use some tools, or get their hands a bit dirty.

But I don't see Mexican laborers loitering outside my Home Depot, loitering on the street, or anywhere else. Or spamming up the Facebook groups with "hire me" ads. They're all busy on the hundreds of State road construction projects, new housing developments, etc. since Texas is on fire with growth right now.

We have a local guy, (not Mexican) who is an expert mechanic. He fixes cars/trucks/tractors/bobcats/lawn mowers/small engines/etc. He will never starve. He is always busy. Zero danger of him running out of work in the next 50 years. And he's in his 60's.