With $1.0 billion you could invest $10K into 100,000 startups or $100K in 10,000 startups. Surely you could change the world, leave a legacy, and simultaneously generate a profit on that kind of investment, no? Why doesn't somebody do this?
because you could never assess the viability of that many startups. people would end up coming up to you with made-up business plans just to soak you for 100k. frankly you would be better off just seeding college scholarships.