well, there are 2 different parts to it;
the development, which is in the hands of a small group of people, which means it's centralized, but that's about the internal system, while it's countered by 19 witnesses
but I'm referring to the votes; there are about 30 whales that have so much more power than the average user, that a vote of the average user simply doesn't matter ... and that's why people are leaving in droves
whether or not a posts starts trending totally depends on those 30 whales, if they don't vote for your post, you get absolutely nothing