Why doesn't pve have pvp combo structure?

[Daeriion_Aeradiir]

(also i gotta say Daeriion, I always confuse you with myself on first sight as our faces look so alike XD)

Ayy, pale skin Xaela partners!

As I said, there are at most two jobs that use a straight 3 button combo.

No matter what the rotations tend to be self centered. Most of the conditions that determine what button is to be pressed are internal to the player character. Combat should be more reactive to the opponent. Rotations shouldn't really be a thing in RPGs. It should be based on the needs of combat. It's all regressed in recent years and today's designers are kind of short sighted.

Simple.

make combo chain buttons for each combo. for example, SAM currently uses 6 buttons for its current GCD rotation buttons:
-hakazae
-Jinpu
-Shifu
-gekko
-Kasha
-yukikaze

There are 3rd party add-ons out there I've seen videos of that condense all three combos into just 3 buttons: gekko combo, Kasha combo, Yukikaze combo. bam, 3 buttons of pointless bloat saved.

it'd even work with combos that share the 2nd button input, like WAR/PLD:

Goring Blade combo & Royal Authority combo. Both combos start on fast blade, then both buttons dynamically update to Riot blade, then after pushing riot blade, you just select the combo ender you want. 4 buttons (Goring, RA, RB, FB) condesned to 2 (Goring & RA combos)

You could do the following for these jobs:

WAR: -SE/SP combos, 4 buttons down to 2.
PLD: Ditto
GNB: Gnashing Fang combo condensed to 1 button, Solid Barrely combo condensed to 1 button. 6 buttons down to 2.
DRK: SE combo, 3 buttons down to 1.
SAM: Explained above.
DRG: Full thrust/Chaos thrust combos. Wheeling Thrust/fang & Claw condensed to 1 button since they're mutually exclusive.
NIN: Armor Crush/Aeolian edge combo. DwD & Assassinate paired together due to mutual exclsuivity.
MCH: clean shot combo. Hypercharge & heat Blast could theoretically be paired together due to mutual exclusivity.
DNC: first two stages of their combos can be condensed. If the code allows for it, 3rd stage hits could be condensed as well.
BLM: leylines -> between the lines due to mutual exclusivity. Fire IV <-> Blizzard IV due to mutual exclusivity due to astral/umbral stances.
SMN: Dreadwrym trance, Deathflare, Summon bahamut, Enkindle bahamut, Phoenix Trance and Endkindle phoenix could literally all be 1 button if you want to go extreme due tevery single skill being mutually exclusive from each other and requiring the skill before it in the chain to be used to unlock it.

At the end of the day, Job button culling is going to happen. Square makes it evidently clear not just in practice, but Yoshi-P himself has said passing quotes on the matter that they desire every job to be within a certain range of buttons. So the options are to let them condense rotations to hopefully avoid them touching actually interesting parts of our kit rather than the utterly mindless, mechanical, every player will have forged into muscle memory and never have to pay attention to part of their toolkit, or we keep combos uncondensed and it's guaranteed OGCDs and actually interesting parts of our toolkits will be getting cut.

Pick your poison. I'd rather they get rid of pointless bloat so that way there's a chance we don't experience a SHB 2.0 with job gutting.