You're describing unicorns though. They are very rare and most people starting businesses today are not building the next Facebook unicorn (no matter how much they might want to pretend they are).

I don't think an exit is the same thing as building a successful business. I wrote about this 10 months ago if you want my full thoughts on the topic. Being bought up may mean you built something valuable which could have some day been turned into a successful business... but if never made a profit, wasn't it just bought out by a successful business just because it might have some day become a threat? I get that I'm over simplifying things as many publicly traded companies purposefully operate at huge losses in order to put money into R&D and marketing and have more control over their quarterly reports (i.e., they could flip a lever and be profitable right away, but are more interested in growth). I'm more talking about individuals working to build a business who haven't been told the whole story of how hard it is and how much work it takes.

I guess I just have too many friends who did the "start up" routine and ended up with nothing to show for it but wasted time.