If you invest $20,000, to get 134 ths/sec. and such a hash rate gets you $105 per day, and each week you have to reinvest $100 in order to continue getting a similar reward, how much have you invested after the first week? Is it still $20,000? No, it's $20,100.

Now, you still have the same buying power as before (after considering difficulty increase) but you are also beginning to increase your investment to see such gains.

Do you understand what I'm on about now?

Stating that a $20,000 investment will get someone a $35,000 return, while leaving out the required reinvestment needed to maintain the reward level over time is misrepresentation.

You are not investing JUST 20,000. You are investing 20,000 PLUS regular, most likely weekly, investments in order to maintain your reward amount to get to $35,000.