Playing a game to have fun and playing a game to win are two different things, I've stated this elsewhere.
Playing a game to have fun means this fun derives not from winning, but mere engagement or struggle with the content.
Playing a game to win means to want to obtain a sense of omnipotence and control over the content, which is earned through honing one's skill and obtaining mastery over the subject.
Some people seem to be suffering the delusion of wanting to derive fun from "winning," but not wanting to put in the effort that will earn said "winning."
I agree. I'll just emphasize the 'some' part of your statements.
Winning without challenge is pretty boring, so probably not fun, and setting the challenge level well is necessary for players to have fun. That's why I don't like the 'get good' statements, as one players good might be another players very poor, but that shouldn't exclude the 'less good' player from playing if they want to, and it's probably in FD's interest to have those players playing and buying content too.
Yes, some people posting in these threads just want to farm RES, and are seeing that aspect of the game made less lucrative. Personally, I don't think farming should ever have been in the game, but that's just me. Others are commenting because they see the possibility that they will be pushed out of the game (which includes being able to progress towards goals, whether that be credits or ranks), and they would rather that didn't happen.
Effort does not mean necessarily getting better, people will plateau, but they are still putting some effort into playing the game. And as you imply (I think), this game isn't really 'won', it's just played.