they often mysteriously suggest the article that's paid for the most promotion.

That's precisely what is being done. Pay a bot, get an upvote. The bots reward those who pay the most to get the biggest upvote. In that sense, it's a plutocratic system. The more you have to put in, the more you can get out. And, because the bots are limited in how much influence they can have, those in who buy in early and buy in at top influence level squeeze out everyone else who want in. As a result, the rich get richer.

Now, you can start small and work your way up, paying bots a little at a time until you can afford to pay them a lot at a time. But, the expense to the rest of the system is that quality goes out the window while mediocrity rises to the top. Once you know you can influence the system to boost your rewards with minimal effort, why spend your time writing high-quality posts that can attract human attention?

And I'm a firm believer that no matter what system in play, there will be those who figure out how to game it.