Why vertical progression is poorly implemented

[Critical-Limit]

There is no way FFXIV's general playerbase would be happy with that, given how people already dislike needing to grind various things to progress. People want to be able to quickly get into endgame content (to the point where even needing to gear up via Law tomes/Alexander NM already bothers some players), and adding materia-gates to end-game content would defeat the purpose of catch-up content like Hunts and 24-man Raids, which are meant to help people get into or progress through more difficult content.

WoW already did this and they ultimately abandoned it because it made the barriers for newer players too high.

So you didn't read what I said.

I didn't say gate fights behind anything. It's just BiS if you need it. The fight can still be won w/o the earth resistance. It's just if you want a faster or "safer" run. That's a choice. Hence horizontal.

Will some people try to require you to have it? Only if they know you can't do mechanics

[Alahra]

I didn't say gate fights behind anything. It's just BiS if you need it. The fight can still be won w/o the earth resistance. It's just if you want a faster or "safer" run. That's a choice. Hence horizontal.

People will definitely require it if the fight is designed in any ways such that the resistances are actually significant until you can overgear the content. It's just another form of a VIT/HP check, really. For it to not be necessary, it would need to not be significant, and then you have a choice that has no impact (so why would anyone bother actually farming the resistance gear?).