Startups are high-risk high-reward. That doesn't necessarily mean they're a bad idea. Expected value can be positive even when probability is low. Moreover, a lot of young people can afford to take a chance on something. If you spend a few years living with your parents and attempting to create something, and you fail, you still have several decades of your life to go punch a clock at Big Corp.
And even if you fail to become Google, you might still make a living. Some people would gladly make a modest income doing something they love, with the possibility of making more, rather than working for someone else making three times as much but doing something they hate.
As for what good comes of it, just think about it. Where do new companies come from? Should we have no more of them? What would happen then?
I think one should argue that starting a business is high risk, mediocre reward. Most businesses just kinda trudge along, not leaving with the fairy tale returns of FAANG. Those are unicorns for a reason. Most of the businesses I've worked for, some of the founders are still working there and while they are pretty well off, they either havent sold yet (no big payday) or they made a meager sale netting them a very good pay, but probably averaged less than an engineer in SV on a 10 year horizon.
In SV, if you’re a founder then it’s medium-risk, high-reward. You’ll be propped up by investor funding, have acquihire>exec as escape route, and in the slim chance of actual success you’ll range from rich to mega-rich.
For non-founders (employees) it’s high-risk medium-reward. An acquihire will make you a rank-and-file employee, and if the startup is a true success you might still only bag a moderate sum, thanks to your tiny sub-percent of equity. Only huge IPOs bring wealth to non-founders.
And even if you fail to become Google, you might still make a living. Some people would gladly make a modest income doing something they love, with the possibility of making more, rather than working for someone else making three times as much but doing something they hate.
As for what good comes of it, just think about it. Where do new companies come from? Should we have no more of them? What would happen then?