The scenarios are greatly simplified here, so it's hard make direct comparisons. But, on the surface it sounds like you're assuming the investment size stays relatively constant.
You might invest $10M in a web-type startup this year, and $1B in a radical new solar panel manufacturing facility 2 years later that promises to halve the price of solar-watts, etc. It also assumes that everyone wants to reinvest 100% every year, you'd get some investors who would be happy to just make back the $20M they lost in another market, and not keep doubling down.
So, I think the model is sustainable for longer than you might first guess.
You might invest $10M in a web-type startup this year, and $1B in a radical new solar panel manufacturing facility 2 years later that promises to halve the price of solar-watts, etc. It also assumes that everyone wants to reinvest 100% every year, you'd get some investors who would be happy to just make back the $20M they lost in another market, and not keep doubling down.
So, I think the model is sustainable for longer than you might first guess.