1. Many trades also are your own business, and can immediately scale for income - many plumbers, electricians, etc are millionaires with a small team of employees less than 15.
2. Google offers free marketing certification for this reason as well, it's not impossible for marketing/seo people to make 100k annually. It's very, very common.
3. Many colleges are not worth it and is debt- look at most state schools and you'd see a semester costs minimum $45,000. Yes there's community colleges.
4. Even community colleges require loans, and have programs of financial aid that is really "apply for fafsa, apply for stanford loans and then have pipelines for private debt.