I think it's because 11 was heavily team-based. You HAD to communicate to get help for your subjob unlock. You HAD to communicate to get into a party of 6, it forced you to break out of your shell and socialize because after level 10, it was really difficult to level up generally speaking.

In XIV it's more structured like WoW in that you CAN go party based, but certainly your're capable of soloing. Also a lot of linkshells share Guildleves and do them together, so it's all kept within the linkshell.

Couple that with the fact that a LOT of players are new and focused on mastering the basics, and the community is small(er) and it explains partially why it is what it is. Things will change over time