Keep in mind in a lot of MMOs, it was expected that Healers only used their damaging abilities in solo content. In WoW for example, Vanilla, BC, ARGUABLY Wrath (arguably because Tanks could practically solo Heroics), and Cata moreso than most (I don't remember Mists, but think it was like BC or Wrath), Healers were expected to NOT use damage abilities unless they didn't cost MP, because MP management was actually a thing. This was most true in Cata, because they also hit like wet noodles, meaning you often had to devote GCDs (well, WoW's equivalent) to chain casting your weak, long cast, low healing but mana efficient cure so that you wouldn't get overwhelmed later. It was actually a big deal when Resto Druid Wrath became 0 mana cost, and Resto Shaman's Lightning Bolt actually helped them recover mana, because before then, they just didn't do much DPSing.
There wasn't an argument of "I play Healer to heal" because the community-wide position was "Healers should heal only". It was so strong, there WASN'T a "Healers should DPS!" advocacy group until Wrath (because content was often undertuned), which made Cata an even stronger wake-up call. I think the next place it popped up was around Warlords pre-patches with ONE exception, which was Mistweaver/Fistweaver Monk, because it was designed in such a way it could heal in melee by doing attacks, and Disc was reworked into a similar vein - Disc before Mists (or was it before Cata?) was just a somewhat weaker Holy Priest that used Power Word: Shield more. Now, this was never IRONCLAD - some Healers it was more and some less (Holy Priest, for example, had very mana INefficient attacks, like Smite, but PLD had some low mana costing attacks on short CDs that could be useful for the party, like Judgement of Light/Wisdom for the party/raid to generate health/mana by attacking the boss) - but it was generally given that unless you were using specific classes/specs, you did not do damage unless there was just no healing that needed doing, and then the damage you did was the stuff with no MP cost ("I'm going to WAND you to death!!") unless you just ALSO had a big surplus of MP and were probably in the party with the Shadow Priest mana battery.
The WoW community strongly held to the "healers should heal only" position because its own roots were players coming over from Everquest, where Healers typically DID only heal, often in turns with other Healers, with some sitting/meditating (IN BATTLE, mind you) for mana recovery when it wasn't their turn to be actively healing.
So no, FF14 is not the first game - unless you've never seen WoW in its heyday? - that had this attitude, nor is it "the weirdest box" for people to think "healer, the role that heals", nor "anti-reality".
It's not even that odd in FF14, since ARR and arguably HW for WHM's played this way as well for most content/most players. Partly because a lot of ARR players were either coming over from FF11 (where WHM also did the heal/buff only thing) or WoW (where many of its Healers, including the closest WHM parallel, Holy Priest, also did the heal/buff only thing for the most part). Note that while modern WoW healers are more offensive (even Holy Priest) like FF14, that WASN'T the case back in the day, nor how players approached it due to the Everquest roots.
Indeed, it's very much true that MMO healing originated with "healers should heal only". That is the original and default state of MMO healers.
Exactly this.
Hm, maybe so. I wonder what it'll be...
Though honestly, SCH could do with 1-2 less buttons...but meh.
NOW, yes. That wasn't always the case. In BC, Holy Paladin had just Judgement, I think. Excorcism specifically for Undead, and Holy Shock if you weren't using it for healing. Judgement and Holy Shock each had CDs, meaning you couldn't spam them (the CDs were relatively shortish, I think Judgement was 30 seconds at the time and Holy Shock may have been similar). Late BC and into Wrath, Judgement's CD was lowered to I think 6 seconds. That was your attack "rotation". Judgement of Light/Wisdom every 6 seconds. Oh, and you got to use Hammer of Wrath every 30 seconds or so when the enemy was in Execute (less than 20% HP) phase. Oh, and you only had two general use heals, Flash of Light (quick, fast, mana efficient, relatively weak) and Holy Light (slower, more mana costly, big heal)...and Holy Shock. Paladin didn't get their first AOE heal until the Cataclysm pre-patch, not counting that one Wrath glyph that made either FoL or HL do a light splash heal (maybe if used on the Beacon of Light, I forget). I think Consecration was still a Protection or Retribution talent until...Wrath, maybe?
I'm going to say Holy Priest had only Shadow Word: Pain, Smite, and the one with the CD (30 sec, later 12?) that did the fire from the sky and put a holy burning DoT on the target, and Smite was HORRIBLY mana inefficient for the damage done, so you couldn't chain cast it. I remember leveling it with only three abilities and using some Disc talents for Wand Mastery (autoattack - yes, seriously, this was the norm) until the Shadow tree got to Shadowform around level 40 or so. Then it was Mind Flay spam for Jesus until level cap. And that was in BC with a Blood Elf where I had a second DoT (I think) that...I think they later got rid of all the Race specific spells like that. I think they picked one or two to make baseline and dumped the rest. And then later, dumped those as well.
Also: Stop using "Sylphies" as a derogatory term. Actually, just stop using it at all. It's not ever going to help you. And if you have to accuse people who disagree with you of wanting to be carried, you need to reevaluate your (ad hominem fallacy) position. At best, it makes you seem a toxic person/jerk, and that's at best. Especially since most of those same players ask for the game to be made harder, but on the HEALING side of things. And I don't know what FF14 players you know, but I know of no one that would be "absolutely delighted" with a DoT + passive HoT pulses and a single AOE 1500 potency heal. I highly doubt that would, in fact, be "the most played job by a mile".
But hey, only one way to find out...
No, it really doesn't.
It's like I said, most people that picked up FFXIV originally came from games where the norm was that Healers did few or even no damage, and if they did, only did so during specific times and once they really knew an encounter and knew when it was safe to do so and that they'd have absolutely no mana issues doing so OR were playing a class specifically designed to do some damage to augment or facilitate...its healing.
And no, the CNJ questline isn't everything, and the SCH quest only talks about healing and shielding, not about DPSing. But we've had THAT conversation before here...