It isn't minnows self voting that causes rewards to be concentrated in a handful of accounts. Minnow votes worth a few cents are only of impact in large groups.

However a whale self vote can be worth $1000's. Imagine if you could give yourself $1000's every week if you didn't curate the posts and comments of others. How motivated would you be to keep that money?

It takes tens of thousands of minnow votes to equal one whale vote worth $1000. This income stream is very competitive with the native desire to curate content. Too competitive. I am amazed at every curation vote whales cast, because each time they do this, they are giving away that money instead of putting in their wallets.

It is hard to expect them to do otherwise on a platform that is designed this way. It is a design issue, not necessarily an issue of human greed. The weighting of votes by personal wealth just prevents fair distribution of rewards in the way the developers intended, so I think votes need to be weighted by reputation, or equal.

This would enable capital gains to inure to substantial investors (by appreciation in the value of Steem, driven by the growth of Steemit, just as stocks increase in value as companies grow, and investors in stocks achieve gains), in a platform that encouraged curation, rather than made it almost impossible for those who have to forego large income streams to do it.