One of the trends I’ve been noticing over past few months is I’m getting smaller votes from the same people. It’s not that they are giving me a lower percent. It’s that they have delegated a large holding of their SP. In their wallet you see them being paid out every so often for doing so.

I've seen the same happen and read others reporting this.

At some point there got be that breaking point where certain types of posts only show up in promoted section since they are in fact being promoted by buying the votes in the first place.

I think this is on the cards down the road, we can hope :)