And so, in a way, whales here on steemit can also be viewed as Oprah. There (and I'm just speculating here) ought to be a whale on steemit who has made his success from zero, just by joining early, without any initial investment.

Granted, it is easier for somebody rich to become even more rich through steemit (like your Oprah example), after all, that is how it always has been. Money is used to make more money. In this case, outside influence, conjoined with an extensive amount of money could be used to abuse the reward pool.

My point is that, without either commiting - in case of Steemit a reasonable amount, and in case of Bitcoin a large amount of money, it becomes only harder with time to make as big profits as the early adopters.

After all, there was once a time when nobody knew Oprah.