I'm unsure about that. I read a in-game book about an old king of Skingrad that won a battle against the Allessians and in the book it mentioned his armor was the best in Tamriel because Skingrad had the best leather-makers and leather was the only armor available at that time. And that time was after the fall of the Ayelids.
Huh? Not sure what point you are trying to make, but if it happened after the fall of the Ayelids, then it happened after Pelenal and his [censored]in armour, so i'm sure they had access to more than just leather armour. Also, why would Skingrad fight the Allessians?
I don't get why so many people have this idea that almost all Altmer are mages. Sure, they have a great talent for magic and mages might be much more common among them than among most other races, but just because 90% of the people who play Altmer are mages doesn't mean that 90% of the Altmer in Tamriel are mages. For eample, the first Altmer I ever ran across in a TES game was a commoner who couldn't cast any spell at all and Morrowind's master trainer for heavy armor was an Altmer who worked in the Vivec City Arena.
The Altmer still have plenty of use for armor. Their armies might have more mages than normal, but they still have archers and infantry as well and those guys do need protection.
Aside from the typical Altmer frailty and considerably lower STR than most other races, they also typically seem too snobby to be foot soldiers, though it is clear that not all Altmer stuck up (or else the whole civilization would fall from lack of laborers).