I've worked for two startups. Both really did want to change the world in good ways. Yes, we wanted to get rich (in neither case were we exactly successful, although they weren't failures in that regard either), but "milking future generations for cash" didn't come into it at all. Making something people wanted did.
There are plenty of scammers in the startup space, but that is hardly the definition.
System would be balanced if seeking profits and seeking exits was similarly valued and respected, if VCs would invest money looking for stream of dividends as much as exit/IPO of the company... But that would take average P/E about 5..8, not 25-30 it is. Till then, and as long as "revenue business" is a derogatory term, we can know that startups are little but a generational Ponzi scheme.
Some startups take cash and turn it into useful things that benefit future generations. Things like medical breakthroughs for example.
Without that cash, those useful things will not be created, they will just live in someone's head as an unfulfilled dream.
Some use it to make things that make people happy, like games. Don't discount the benefit to future generations of having things that make life happier.
And don't discount the goodness of people being able to work on their dreams, either. It's not just rich people that get to play the startup work-on-my-dream game. Poorer people do as well, admittedly with less chances at it, but it happens often enough to count.
Some even have benefitting others, the less well off, be an explicit goal of their startup. Heck, some even invest their time and money into non-profits for such benefit to others. (I did that.)
And some startups are bootstrapped by people's own personal money that they earned doing a regular job. Imagine that.
Also, i know that the only alternative is the Communism, and i was born in the Soviet Union and old enough to remember a lot of it, and that's enough to prefer the current system.
If you want people to think of David to the incumbent Goliaths, something with a mission to introduce something new and breakthrough to the world, a conduit for the wild dreams of youth to come alive, call it a startup.
If you want people to think stodgy, established, nice stable place to work and pay your mortgage off for 30 years, but no changing the world, call it a business.
Like any branding, that will affect who approaches you and what opportunities you end up with.
Just look at YC. Only two YC backed companies have ever gone public - DropBox and PagerDuty.
We are all riding a horse we know won't be around for much longer. Most startups exploit the shiny object factor, gullibility, poor education and plain stupidity of people who shouldn't have had any money to buy stuff in the first place - and they soon will not have - but above all they exploit the pyramid of debt as trillions upon trillions of valuations and exits that the founders cash out are the printed money that doesn't really exist. When it will be time to pay it back, it's better to be as far as possible...