So if people don't talk to each other, why even bother run with other people? Really, they might as well be NPCs and most likely they would play better than most people I have encountered in DF. Of course people run from instances they don't like aswell but if you openy your eyes and ears, you'll notice that a lot of people are sick and tired of constantly being forced to group.
The problem with FFXIV is that there is not even the possibility to solo. You underestimate people wanting to play with others and overestimate the need to be forced to play with others. If a game needs to force people to group, it simply means that the devs are not able to create content that wants to make you group with others. And why is that? Because the game caters to bad gameplay. It does not encourage you to improve your abilities by challenging yourself. It does not push you to develop strategies to avoid a catastrophe. And why would you improve if you can find someone that will carry you?
I'll give you an example: DDO. I recently started it again (while still playing FFXIV) and it is amazing how much the game challenges you to not just run head first into mobs but to THINK. And while a lot of normal dungeons are solo-able, there are also places where you need others in order to fulfill certain requirements. Also, of course you will need to group up for raids. I have many reasons to love FFXIV but believe me that the DF system is NOT one of them. The DF system is there because there is no possibility for people to not group up.
A truely hard dungeon requiring me to group up with people to beat it is different from a faceroll place needing me to bring people along because I can't enter the place otherwise. Why can't i by the way? Do I need 4 people to push open the door? do I need a Lala on my shoulder or the guard won't let me in? One has to wonder....