The game does not facilitate player growth or the formation of friendships. You can have reached level cap and slogged through the 400+ hour long story and have never understood how to play your class or have found a friend.
Oldschool MMOs were hard. Take Vanilla WoW for instance. The world had packs of dangerous mobs that were very risky to take on by yourself, and it would take a long time to get to wherever you wanted to go, so you didn't want to die, and there could be a considerable monetary loss in repair bills and food and potions and arrows and so on. You could theoretically solo to cap farming easy mobs but it would take a long time, and you would be in the dark without other people sharing information with you. So you really wanted to play in a party with other people. There was no LFR or Duty Roulette to automate grouping for you. So you had to actually talk to other people and form bonds with them over your several hour long play session, be on your best behavior if you wanted people to group up with you again and for you to not get bad reputation on your server. And then you network with more and more people and before you know it, you're forming a big guild. If you didn't already know social etiquette, you would. If you make a mistake, it's okay because you're with friends and they will teach you how to get better.
Then LFD happened, where players could click a button and then be placed into a group without needing to socialize, for the purpose of doing 15-30 minute long bite sized content that was not difficult, and the stakes were further reduced as repair bills and food and potions and etc weren't expensive anymore. So people could spam dungeon roulette to level up and reach endgame having never formed a bond with other players or learned how to socialize. A mercenary mentality seeped into the game where players started viewing each other as cogs in a machine delaying them from getting their chores done. If someone is new and botches a mechanic, there are no bonds of friendship. Too much of a bother to stop and try to teach him, and those who do take the time to try to teach are often met with explosive outbursts. So it's easier to just kick the "underperformer" and replace them. This then leads to the playerbase becoming increasingly antisocial and the arise of toxicity as the mature oldtimer players are gradually replaced by a new generation.
FFXIV is no different with its roulette system, it's just that the player behavior is expressed a little differently due to the draconian chat policies. Rather than a player who botched something being instructed how to play better and exploding, he instead just silently quits.
Here, the game design of FFXIV (long cutscenes that can be interrupted by a boss pull) pits two different demographics of players against each other: the MMO audience where you have a group that is trying to minimize total manhours wasted, vs the individualistic mindset of visual novel players who want to go through the story at their own pace. As FFXIV's claim to popular fame is its story, you're naturally going to get a lot of story focused folks who aren't thinking about a MMO player's perspective on timely pulls.