Its very hard for us minnows. I have experimented with using bots. Although they dont seem to be profitable they do seem to give you more exposure early on which is good.
I think they are being abused by some people who, as you said will just throw large ammounts of money at them to get their content in the trending sections. I dont think this does anything good for Steemit as a whole in terms of quality content - people know they can just publish an article and pay for it to be seen in the trending section