Other than the necessary use of the Interregnum epoch from TES lore to justify this TES themed PvP MMO, ESO has always been a blatant cut and paste of single player TES content for its PvE content.

Perfect examples: superficial re-meshing and re-texturing of Skyrim dragons for Elysweyr dragon content. Where in the TWENTY FOUR+ YEAR history of TES lore have DRAGONS ever been affiliated with the Khajit or Elysweyr? Answer: Nowhere. ZoS saw the still astronomical success in replay value single player Skyrim is enjoying to date. And so thought it strategically best to import one of the most defining features of said single player DLC aka Dragons. Which ironically, IS NOT the reason why Skyrim remains so popular among the single player fan base to date. The concept of open world sandbox in which the player has 100% control over their world environment and character customization -- FOR FREE -- appears to be lost on ZoS to date.

For TES single player fan base, what that means is:

• If a player doesn't like the way their mount looks, or wants to fly unicorn themed Indriks in their game, they can change it.
• If they don't like the way the weather works, or how the environment looks, or the very lighting itself in Skyrim, they can change it.
• If a player wants to use adult content mods to enhance their game play in Skyrim, they can change it.
• If a player doesn't care for the PvE or NPC PvP level of challenge in their game world, they can change it.
• If a player wants to add new worlds with tons of quests to explore/enjoy, they can change it.
• If a player wants to be a merchant struggling to build a trade empire in war torn Skyrim, they can download or write economy mods to change that.
• If a player wants to be a world sophisticated collector of lore items to display in their own personal museum, they can change it.
• If a player wants to be a humble farmer who transforms into a Daedric werewolf/vampire to terrorize the world by night, they can change it.
• If the player wants to be a simple miner, hunter, treasurer hunter etc. who does simple fetch quests for their village or city hold NPCs on the side, they can change it
• If the player aspires to be the most important noble/Thane/King of the realm, and/or do nothing but build and own mansions, cottages, and castles all over the game map, they can change it. And give their NPC subjects jobs with a thriving economy while they're at it.
• If a player especially doesn't want those annoying flying Aedra lizards -- aka dragons --being irrational psychopath arsonists burning everything in their game world, they can change it.
• too much to list here......

This is NOT the case with ESO which--by default of being an online game--ZoS retains control of all game world DLC content. Which by default of being an online game, you the player will always have severely limited ability to customize your game. And are limited to simple UI/text mods (ie LUA based scripting). And since. by default of being online, you've agreed to either grind ZoS servers or pay them millions annually to buy increasingly unoriginal and recycled content like Indrik mounts.

The only means the player has to address this inequity is to complain to ZoS like they are here in the forums. However, this won't change the fact ZoS has their very successful business model with this MMO. They've found an extremely profitable way to add new DLC content to ESO at the least cost. i.e. refurbishing and re-marketing existing single player TES game concepts from previous single player TES games as new DLC for this ESO.

Perfect example #1: the direct port, slight re-mesh, and re-texturing of Alduin and his Aedric fire breathing cousins from Skyrim

Perfectly blatant example #2: the direct port of Skyrim's Solitude landscape directly ported into ESO for the upcoming DLC. That modern day Solitude city/landscape design is starting to make me wonder the ZoS devs really believe the ESO fan base is that ignorant.......

The bottom line is the OP's post is valid in that the lore of the TES universe is being bastardized by ZoS business model in the store. Selling increasingly unoriginal, and knock off single player TES content which do not comply with established TES lore.
But this is NOT something ZoS will ever care to address in the future. They're NOT going to do anything to jeopardize the lucrative millions they're making to date in profits. Not when they can passively reap a windfall off superficial DLC content from the more impatient, impulsive, and high disposable income ESO fan boys who keep throwing money at them in store.....