Well, you'll need to cite your source for your 6 straight years of declining enrollment because local enrollment is down but international enrollment is way up. They make more money enrolling international students and out of states than in-state, local students.
Private colleges are in general more expensive than state run colleges, especially if they have prestige. Also, your college needs to be accredited in order for your degree to matter. Employers look at degrees and differentiate them by school's prestige.
Whenever I read about someone saying colleges are scams, people are brainwashed, etc... I'm wondering if they actually know what they're talking about. If you're talking about gender studies or music histories major, then I agree, those are useless. However, my dear misguided poster, if you're talking about hard science major, then you'll find out that a majority of them can very much calculate/manage/handle their financial life just fine. In fact, going into a 4 year degree in a hard science such as engineering (mechanical, electrical, chemical) and compsci will almost always guarantee better job opportunity than having no degree.
The very fact is that engineering students do not have time to waste on social justice like safe space and cry box and they tend to be condescending toward non-engineering students. The people who actually make their money worth of college are these guys. They can think for themselves just fine, so you don't have to worry about being left-leaning brainwashed. In fact, they tend to be mid or right leaning because they actually make more money than no degree people and they want to keep it.
I'll counter your prediction with my own. AI is bad for everyone, more so on the no degree people because they can be replaced by robots controlled by AI. However, it's a long way until AI is capable to operate on their own in a dynamic environment, (controlled environment is decent, dynamic not yet). The people who work with AI to develop/test/modify/discover it will make a lot of money. The people who can tell AI to do only what they need will make a lot of money. Companies will still hire people with degrees because if they can't find workers locally, they will hire people globally with degrees. They're already doing that now. I think the chance that the entire world will eventually abandon colleges is near zero, unless Armageddon.
Just like Steemit, people with money make the rules, and people with no money will flock to them. Corporate will always find someone to hire because they're fucking rich.
Thoughts can be discovered by oneself but to repeat the entire process of molecular model to quantum mechanics to adaptation of electronic circuits last multiple lifetimes. If you're talking about hand waving, philosophy speaking, yea sure. Not science knowledge in the past 100 years, let alone newly discovered ones.
RE: What will become of the economy if colleges fail?