my question is: shouldn't this create fierce competition,

It should, but a lot of talented people go into engineering. Untalented people can't do anything. The trades have been traditionally low paid and low status (happily now changing). So yeah, supply has not caught up with demand and that hasn't changed in the last couple of decades.

with everyone wanting to start their own business? or is there enough business for everyone, and if so, how long is that going to last?

There's enough business for everyone for now........ how long will it last: no idea, noone can predict the future.

The general statement people make about trades isn't wrong, it's decent pay and no debt to get there, but it's hard work. Being your own boss and breaking into the big money is high risk though.

If you're not ambitious, intelligent, or come from wealth, and a technical degree is out of the question and your known options are go to college for 4 years and rack up 100k in debt to get a 50k/yr management/office job VS get into a trade and be payed 30k to train and 50k after 2 years, it's a much more lucrative option. You can reach 90k as a senior electrician in my city which isn't bad living. The cost savings on the student load debt will put you further ahead than a similar peer.

If you get good in a trade you can pimp yourself out and break 100k but it will require ambition, startup funds, the ability to weather nearly no business for an extended period of time. Not many people have that. There's not that much competition, but what competition you do have IS fierce when you're a no name dude with a van and a dream against reputable companies who have a name, a fleet, fast service, 24/hr 365 days/yr people to schedule/come out and do the job. How do you beat that? Price? The big boys get backed up sometimes and you can find customers desperate for same day service, and sometimes during bid walks you'll find the customers sour at a competitor who did a bad job before. It's not easy which is why there's not many people doing it.

Im a plumber, trades are pretty horseshit, everyone goes on about how trades make so much, but it's only the successful business owners or sub-contractors really making the coin.

Not everyone wants to start a business, nor is everyone good at running a business.

The guys deploying their own businesses are generally able to do it after acquiring the following:

1) becoming a journeyman in the trade and getting a bunch of experience 2) having an organizational/leadership side - you are not just a tradesman anymore. You are a manager, bookkeeper, salesman, estimator. 3) having a customer base built up from either experience in point 1) or along some ethnic line ( Chinese people like hiring Chinese plumbers). 4) starting capital

And if you pull all that off you are still at the whims of market forces or fuckfuck games from larger entities you will be subcontracting to. So quite a bit of winnowing process.

"Extreme shortage" my ass. There is an extreme shortage of skilled people willing to destroy their bodies for slave labour wages. There might be a shortage in some specialized technical trades where the path is not as linear, but not for regular shit like carpentry. In my inspection trade if you can make it to API inspector your base could be 65/hr, but its a tough climb to get the experience and tickets.

Plenty of carpenters from murica online saying their wages have been flat for 30 years and how the trade isn't worth it anymore

It takes a slightly different and rarer person to have the courage and perseverance to start a successful business making 6-7 figures. Sure there are dorks who got a good hit of luck with a lotto ticket, crypto pump, trend creation which benefitted business etc. but building something significant in general will take all the positive masculine characteristics talked about here