Well I do think the standards, overall, should be the same for commercial games, be then RMXP or not. Main reason is that someone is charging for the game, so it must be worth your game. Let's not forget that there are many nom RMXP freeware games too.
Anglashel said we could call him shallow, and I was about to do that, not in an offenssive way, but more to show a point: Different values.
Ppl has diferent interests and RPGs seem to group a lot of areas together in different quality degrees and even for each area, ppl may have different tastes: Some prefer dark stories, others prefer lighthearted ones, some prefer anime style graphics, others prefere realism and so on... As much as some value graphics more than anything, others value story more, others gameplay and such.
Those preference matters don't regard quality, but target audience. And there will be a larger group who has more common interests and smaller groups which go for less prefered stuff. Surely that the most secure way is to feed the majority, but if by all means you want to go for something less common, know that this public may actually pay more since they don't spend much money with most releases anyway.
However, that is not to say that even if your game sucks, you can still sell it based on a popular theme. Quality is an issue, the matter is: what is quality? I think it comes on how well made the final product is, or even better: how well it portrays the concept it was supposed to portray.
But this doesn't mean that high quality with a poorly appreciated concept will sell you a lot either.
Where do I want to get? Well big game companies have usually better tools, more and better trained personel and a lot more... that helps with quality, but concepts and originality has nothing to do with that. And to that, any creative 13 yuear old can beat some big company worker. No one can teach you to have ideas, it comes from you.
If I were happy with the modern RPG market for its ideas and concepts, I wouldn't play RM games nor old roms, because in most quality aspects, modern RPGs have an upper hand. Still they doesn't make me too happy when I play, it is not the same feel I had with Chrono Triger, FF6 or some RM2k games I played. They didn't have awesome CGs, neither did they have 3D, nor voice acting, neither crazy battle systems with fury bars and the likes... they just had good ideas which were transmited well enough for me to feel then.
For that I say that I would pay more for a good and original RM game than I would for the next Final Fantasy, Tales or whatever popular series the big companies keep spitting out.