Reasonable point, but I suspect there's a lot of value in simply being listed on Amazon.
No, not really. There is so much listed on Amazon that without marketing to get people to click on a link any book or ebook just goes under without a trace. Single celled organism in an ocean kind of a deal. The ability of people to self publish to Amazon has created this ocean.
First of all, most of those "billionaire dropouts" were dropouts from Ivy League schools with plenty of startup money from daddy already at their disposal, not dipshits coming out of no-name-high-school. Secondly, most of them only left college when they already had contacts and solid plans (and financing) in place for starting their own businesses. They didn't need degrees because they were going to be hiring *themselves*, not having to worry about some HR department that will toss any non-degree applicants right into the trash.
For most of the non-rich, non-Ivy League assholes like the rest of us--we still need a college degree if we're going to get beyond the front door to any stable job. We're not Mark Zuckerberg or Bill Gates.
If you're looking for a "stable job" then go to college. If you're not in the slightest bit interested in a stable job but want to do entrepreneurial things instead, and you have that temperament and want to change the world, then to start singing "I did it my way
"I have not the slightest confidence in 'spiritual manifestations.'" -- Robert G. Ingersoll