Why do long time players play the game so differently?

[MistakeNot]

2016 is not old, it's already way too late to have enjoyed the game at its prime (HW DRK)

Yes, it is old compared to the age of the game. ARR was launched in 2013. It is now 2022.
If you started playing in 2016 you have been around for two-thirds of the game's lifetime. That counts as a veteran player by most reasonable definitions.