I think Intel, Google and Facebook have improved humanity though your tastes may vary and I enjoy Apple's shiny stuff. Those have a market cap of $1.4 tr and it's hard to think of anywhere else with similar output. Maybe like democracy it's the worse possible system apart from all the other ones?
My experience is at least somewhat similar for at least a half billion to billion other people, so I'd say their impact on humanity is "pretty large".
It's not like we wouldn't have basically the same world without Google, Facebook, or virtually any other SV company.
People are just so full of themselves here.
The Valley works well at convincing people that fake money is equal to the quality of real life. Market caps have nothing to do with happiness, health, and interpersonal relationships.
My experience with family life is that happiness, health, and interpersonal relationships are generally much harder to sustain without some wealth. Not impossible, but harder.