I actually think that the players have their blame in this (maybe not totally) because of the whole "let us solo" trend, basically you do have mobs, almost up to rank 100, which would be a bigger chalenge to kill but because mmobs need to be able to be soloed then these will also be the easiest to kill in a party and as such provide the best SP/hour.
This is one of the things I like the least about FFXIV, the ability to solo along with all it's implication made the game too easy, people to lazy and the comunity almost non existant outside LSs.
Well, maybe if they didn't turn the LFP system into a bottom-top approach more people would have been grouping. Let's face it - the folks who came over here initially were all FFXI players, and that meant we were used to partying. Unfortunately, this game and the system in general didn't lend itself well to grouping. The classes weren't really dependent on each other like in XI.
So, between those two issues it's no wonder that people took the path of least resistance. I can guarantee you if the LFP system was left how it was where people would flag up and a leader would build a party, the classes had been clearly defined where each role complemented the others, and the level sync revolution that changed the face of XI was continued here, we would be looking at a very different game than we are now.
If there is one thing I know about the fans of the FF franchise - is they are not lazy gamers who want things handed to them.