That may be true for the technical side of things. However, don't forget your earning power (including willingness/energy to put up with dread work) and possibility to build your professional network. Building savings takes time, esp. if you have or want family. Throwing your best years at your own projects has some risks.
There's also the emotional side to consider. There's a danger of falling into a rut when you have put a lot of effort into something and nothing / or not much to show for.
I'm a long-term side project builder myself. I have been freelancing all my life and taking time off between projects to build my side projects. I never hang in long enough though, which could be the reason why none of my ideas have taken off yet.
But I have to say that I have now basically accepted that my side projects are for fun only and my freelancing is for building my egg nest. And that feels quite good. I think I'd only go into a ownership based startup with the right partner and business model.
After three years I'd surely try to put my project on auto-pilot and do some paid work. Also to gain a new perspective on things.
Not to take anything away from the product (it's great) or determination.
(Btw Steve, we met once in Madrid, hope to be able to come back to geek lunch)