The reason why no one talks in dungons, raids, and the like is because most people, in spite of it being an MMO, only care about "progression", i.e. EXP and gear for the sake of EXP and gear. "Friends" are just a term for people to help you with content you can't solo, or do things you can't be bothered to do (like tank, heal, kite adds, etc.) for the sake of doing "fun" things like DPS.
Thing is back then level sync didn't exist, and jobs didn't have shield or a plus sign to tell you what "role" was. A lot of jobs didn't even grind well unless you had ridiculously overpowered gear (read: be prepared to spend a lot of time ALONE farming and camping to get said gear). Since 1-75 was simply 99.9% PUGs, and most people flock to "path of least resistance" mobs, most people had little incentive to level (or even use) their axillary skills. You have samurai that don't have Archery leveled, Dark Knights not using their magic (and missing spells), Warriors that don't tank, Blue Mages and Black Mages acting like glorified cannons, and I even had a Puppetmaster in Dynamis in full AFv2 that didn't have his healing puppet frame. "Experience" parties are nothing more than a mind-numbing grind with strangers, who only value you if you discard everything about your character to make the numbers as big as possible. That's not counting the fact people are EXTREMELY picky about what jobs to use.
All of this also means when it came time to "adventure" people had no idea how to do ANYTHING in their jobs outside what it's "role" was. If the fight actually had mechanics involved like "reading a chat log and if a mob uses a certain ability stop DPS or you will heal it", "use item X to stop it from using its special nasty party wiping move for 30 seconds", "stay with the party and pay attention to where you are going, don't just run off and explore somewhere", "bring status recovery items and other supplies to make it easier on the healer", and everyone's personal favorite, "read up on fights and know what to do". Most people just want to burn these fights with either BLMs or Melee DPS, and it generally goes wrong 95% of the time.
TL;DR Experience parties suck. Most of the time you do them with strangers, your mind goes numb, and its like being power leveled in you don't know the intricacies of you job.