At the moment it is, but the curation system leads to that changing. The key is for each person to use their 20% upvote each day, especially into the hands of other dolphins or minnows. Whatever your vote is worth, that takes 100% of it in value and puts it in the non-whale pool.
There are also a number of whales who use their votes and SP to help other non-whales. This too only adds to the pace which the distribution moves to the other classes in the pie chart.