I still haven't seen an explanation of why more people at the same time is better than having them spread out over multiple generations. Same number of "Einsteins" (though I don't subscribe to that reasoning), just not at the same time.
edit: parent commenter removed a claim that it was beneficial to have more people working on issues like climate change simultaneously
Insects with individual neurons alive for a billion years didn't produce a single technological invention.
If you need a civilisation where some group digs iron ore, some group processes it into steel, some group processes that into sheets and pipes and tools and valves, some group processes those into chairs and desks, some group uses those to build computers, some group uses those to build wind tunnels, some group uses those to build rocket engines, some group uses those to build rockets, some group uses those to build satellites ... it wouldn't work if your only source of plate steel was 1,000 years old and your only source of valves was some weird pile of leftovers from 500 years ago when they didn't understand your use case at all, and if you're plans for your rocket are that someone will fly it 200 years after you die...
I think it worked? Scientific and technological progress has been great.