If I had to guess, since most people who use RPGM don't know how to code, they have no idea what is reasonable and feasible (see Teary's idea of having an enemy that could follow and interact with you in every location at any time) and since they don't know what they're doing, the game gets buggier and messier with every new addition (making things more and more difficult the further development proceeds).
First, as somebody who
does know how to code, what he wanted (with the Tormentors) is not even actually that difficult to implement. By default, the engine allows you to create events (the enemies moving towards you are all actually Events as well) that can follow the player. He can also make them intangible to the terrain (so that they can follow the player through solid object, if he so wishes). He simply needs to add that event to each Map he wants the player to be hounded by them. I can implement that shit in less than 10 minutes (provided he already has the interaction On Touching the Player already done of course).
The real problem is Feature-creep and laziness. Teary feature-creeped the game to all hell, adding so many variables that, even know, see actual no use as of yet, and likely never will see use, and this, in turn, made working on the game
feel more tedious each time, thus leading to him procrastinating working on it. It became a vicious cycle, that would inevitably lead to more-or-less permanent inactivity.
Even know, if he'd release the update literally years over the deadline, the sheer wait for it would make it underwhelming by default (since the more you delay an update, the more people expect you actually
worked on it; if you simply lazed around for 99% of the time, you're essentially fucked).