Main problem with Just-Dice is likely to be that investment outweighs gambling - driving investment return right down. But even if it only returns your principal it's way ahead of what most people are currently achieving.
Actually the proposition was not to invest it there, but to gamble it there. As you well point out investment takes too long and is too small to please the crowd I'm addressing, as it will never turn half a McChickenBox into "Oprah Rich".
Yes, people have been rewriting/repackaging MP's stuff for quite some time. It's how they learn, and for that matter it's why he writes.