your headline said "most people" -- and the whole "investment" thing is very hard. Which is why you shouldn't frame your discussion with certainties even in the headline. There are enough idiots out there telling people not to bother studying, both in words and by example. You want people hungry to work on tough problems, but they have to know what they are. And they have to see a variety of opportunities out there.
College is NOT an absolute fast track to employment. But it's an excellent reliable way to do that. Plus it's a fantastic place to find out more about yourself, meeting people, friends and for relationships. A lot of people have the college drinking perception. Which there is too much drinking, but there are a lot more ways to meet people in college where you're not drinking than in the working world.
Again just respect the work you and other people have done to get where we all are. Just to say "most people shouldn't go" is ridiculous. We want MORE people going. Show them how to do it in a financially responsible way. If that's too boring then stick to what you know.
I would even go so far to say that OP's anecdotal quotes from friends in "investment research" weaken his conclusion (i.e. I'm (100%) sure I'd be a millionaire if I'd started my current job 4 years earlier. But in order to get my current job, I must've gone to school for 4 years.)
The perhaps hidden point was that it is ludicrous that the best value of a degree is it lands you an interview/job, and not that it gives you as much skill otherwise.
Yup, fair enough! I have no doubt some degrees have greater value in the economy than others, and god knows management degrees (as an example) have their fair share of detractors, rightly or wrongly.
To me that just means folks need to be more thoughtful about the degree they select... after all, a quality, valuable education isn't something you're simply given, it's something you take.
Survivorship bias is real, but so is remarkably low return on investment. Its just harder to measure in people.