Not really. It's a mixture here.
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.