If the game required groups for most content to be completed, I would simply have to quit playing as I don't have the luxury of several hours of uninterruptible free time. I need to be able to put the controller down and leave for a few minutes regularly for IRL priorities. The fact that this game can be played solo for most content is the only reason I can play at all.
I imagine I am far from the only one in this situation. You will say "Well then only people who have time to play should be playing an MMO", but to Square Enix that's a lot of lost subscriptions, and for what gain?

Right now I think there's a good balance. Most things in the game CAN be done solo, but is much faster and gives more rewards in a group. Sweaty content is all group-centric, and the solo-centric stuff is not anything that would even be fun in a group anyway. Don't take away solo content thinking it's going to drive people into group content, because it's more likely to just drive them to a different game.