Rich people can invest relatively small amounts in hundreds, if not thousands of startups through preferentially treated retirement funds and pay no (or little) tax on the ones that make it big.
This is what has made it so easy to secure funding in the US.
Should Europe do the same? There's definitely an ethical dilemma in making the rich, richer for the sake of innovation.
What do you mean? The European rich have always been getting richer via inheritance regardless of innovation. That's a monetary and legal policy hack that's been in place for decades/centuries here which is how the richest families are centuries old.
Investing in innovation instead would be a much needed breath of fresh air and give current generation of youth some skin in the game instead of a defetist mentality that there's no point in working hard because the zero sum game is rigged. So I don't get your point.