Edit: and there are no "open source" tools. You have to buy them, and good ones are not cheap.
I should add that all the people I know who are earning really good money in the trades put in some years, established a solid personal reputation in the area, and then started their own businesses.
Also, in the US (at least west appalachia, but it might be all of north america), it seems that the logging/milling industry has incestuous relationships with the building industry, and it seems to be pretty hard to find cheap wood from clearcuts if you're an independant. The person who hosted me and my familly for two weeks in WV used wood he logged himself for his home and dependencies (he was 70 btw), but even for a contract he got he couldn't use the wood from the nearby mill and imported it from Ohio/Canada. And it was in 2018 so there weren't as many pressure on wood availability as post-covid or right now.
Many people are hired onto rough framing crews with no experience. That's what defines it as entry-level work, IMO. You're saying that people without experience make errors in rough carpentry, which makes it not entry-level. (I would say that makes it "not unskilled" but still "entry-level" [because you can be hired with no experience].)
In EU aa lot of in-built furniture is made out of "furniture board", it's particle board with some veneer. There are a lot of local companies selling that board, you can order already cnc cut and drilled pieces, you just need to specify drilled holes positions and sizes and you can offer custom furniture. Buy some off-the shelf fasteners and you're ready to go. Made a small library shelf this way for myself and it was 2x cheaper than anything ready made, but looks perfectly profeessional. My local carpenter friend orders at the same company, made me a kitchen much cheaper than anything available at big retailers.