In my experience, startup founders who want to get rich want it more in order to have the freedom to work on what they want than to impress people. That could be because we prefer startups whose founders include hackers. On the other hand, we don't just prefer that type because they're more fun to hang around with, but because in our opinion they're more likely to succeed.
I thought I'd need 10m+ to do this, but over time I'm gradually acquiring everything I need due to places like sparkfun, ebay and alibaba for little more than the cost of an average car.
I'm inventing every day (5-6days software, weekends building random projects), learning more than I ever thought possible and loving every minute.
My point is that if this is anything like your dream, it's readily doable now as the cost of doing science is extremely cheap these days. And I've found that productivity increases when I take a break from software in the weekends and do some wet/hard projects.