Originally Posted by
wereotter
This is correct. As a PS4 player I can say that I'm not required to have PS+ membership to access FFXIV, but I am required to have it to access online content of literally every other game I own. I suspect this is a grandfathered in feature as it's the only online exclusive game I'm aware of that existed in the PS3 generation and persisted into the PS4, and I'm certain Square went to bat to say that they weren't going to support making their player base pay both Sony and Square to access the game.
As an opposite example, however, ESO has no monthly fee to Bethesda and does require you pay Sony for online access. Additionally it has a LOT more micro transactions, making it feel more like a freemium game than FFXIV, especially considering these purchases are available and encouraged in-game.