I've been thinking on this one a lot recently. I think it comes down to this one central problem of human thinking which is primarily based on our short life span:
Once a human gets control of a large sum of money, they tend to want to either hold onto it, or make it grow larger.
This is the central issue that I see creating problems. Ned's delegations actually set an example for other whales, but when @blocktrades said he was going to sell his, I viewed it as not a great solution. I believe that blocktrades' Steem would go up in value more if he delegated his SP to builders of communities....my guess is that blocktrades may not know who these people are or may not want to do this....
In a "free" system such as the steem blockchain each participant has it's own agenda. @blocktrades runs a business and I understand why he is trying to capitalize on an opportunity to profit from it.
If we analyze it it's basically a lease on SP. The service can actually be used to grow the influence of a community. If my math is correct at the end of the delegation period you can get a ~17% ROI if you just auto-vote (10 full votes per day).
If a community pools their resources into one account and then uses the delegated SP to vote on the posts of it's members the community can grow it's influence over time (measured in SP).
The difficulty would be to setup some sort of social contract that everyone agrees on.