Sure, it's great for the people who sell their startup, but it's bad for the rest of the world, which might have benefited from the product that was assimilated into the Borg.
I often wonder if that's a good thing.
On one hand, it provides VCs with more incentive to invest in startups, which significantly lowers the barrier to entry and allows us to more easily take risks trying new things.
On the other hand, it essentially guarantees the entire economy will eventually be consolidated into a few megacorps who might not even be good at what they do. It may be possible to compete with them, but instead startups are incentivised to join them.
It's really weird watching hackers defend the idea of monopolies like Google now, at the expense of FOSS. It makes me wonder if Microsoft had been spending more money publicly buying startups back in the 90's if hackers would have defended them then.
On the other hand, as a big company, it's really nice letting the plethora of startups try various approaches and then buying one that is working, rather than making an attempt or two in house. You usually end up with better solutions for cheaper that way.
I think a partial solution to this is to ensure a minimum level of support for say 10 years. A planned and community-agreed roadmap, bug and security fixes. Google could afford it without any practical cost. Founders get the money. Consumers get a product for a decade.