Appealing to the bots is not the only way to get ahead. It is probably not the best way. What I can say with almost absolute certainty is that it is the fastest way. At least, that is the case currently.

If the number of active users expands significantly and/or the price of STEEM rises drastically, buying one's way on to the trending page will become much more expensive and difficult. In that case, I see two possibilities: 1. Trending will be solely the domain of those with exceedingly deep pockets. 2. Other promotion methods will gain traction and gradually replace the bid bots in importance.

To the best of my knowledge, all media platforms have some sort of pay-for-play or thumb-on-scale mechanic. This is quite apparent when examining the quality of content in broadcast television and radio. Typically, the system is something I would consider worse than the Robotic Overlords of STEEM. What I mean by "worse" is that an even greater unearned advantage is given to an even smaller group of people.