It's funny that their weaponary is used all over Tamriel when they're gone. Although I guess Men or Mer smiths could of picked up the recipes.
Except for the fact that making and repurposing Dwemer metal to make
new weapons and armour is next to impossible. It's simply beyond the metallurgical skills of early/mid 4th Era Tamriel. The secrets of Dwemeri metallurgy vanished with them, and even if Yagrum (locked away in Tel Fyr) somehow manages to live to SKyrim's time period, I'm assuming that Divayth or Corprus has taken its toll on the fat Dwemer man: you aren't gonna get anything from him. In the case of Oblivion, where you're getting this commonality of Dwemeri armours and weapons from, it is purely a poorly thought out game issue, a side-effect if you would of the loot scaling.
In the other games where you had Dwarven/Dwemeri weapons and armour, they were quite rare: not impossible to find, but definitely uncommon and certainly expensive enough that only the best equipped people will have any of it, and only the ultra-rich would have a full suit.
Every piece of Dwemeri armour and weapons you've seen in the games have existed for generations, with the newest things till being nearly a thousand years old. As for stylistic differences? Chalk it up to varying cultures adapting the same materials to account for regional necessities. Most Dwemer armour you see in Morrowind, if you've noticed is basically repurposed Animunculi that have been 'cleaned out' for use since most 'proper' Dwemer armour is strictly regulated by the Census and Excise Office and the East Empire Company is the primary trader in Dwemeri artefacts. Presumably, I believe, the Dwemeri armour you see worn in Cyrodiil is the sort of armour that the Dwemeri themselves would have worn: particularly if you compare it to Assyrian/Babylonian armours (in general style) considering that their ghosts you encounter in the various Dwemeri ruins in Morrowind were heavily influenced by that style.