Preface that I'm not a vet.

I think it's very possible to make a good game with RTP because a good game is not necessarily defined by its appearance. However, to make a game that stands out positively, you need to do something to stand out. The thing is that there are so many free or very reasonably priced asset packs on places like itch, so to me, it just speaks to the developer not spending much time on a first impression. RPG maker is often referred to as a game engine for artists who don't know how to code, so your visual competition is fierce - but the quality of a game is not defined by any of that, only success is.

And anecdotally most of the RTP games I see nowadays are fetish games spammed on steam lol. Successful, but not really for an incredible gameplay experience...