You will see what you want to see, but there are improvements and new content.

Is the glass half full or half empty?

I say, "Get a smaller glass."

What you're referring to is called horizontal progression, where instead of lazily raising the level cap and introducing sets with higher stat density every patch to give players an artificial carrot to chase, they instead introduce sets with different stat distribution and affects leaving it up to the player to decide what's worth keeping and what's worth chasing based on their build.

They've not only added plenty of new set in the past half decade, they've made adjustments to older sets in an effort to keep them relevant. It's intended design not maintenance mode.

Whether people are happy with the overall direction of the game is another matter, but I just wanted to point out that distinction.

I think the misunderstanding here is that gear doesn't get outdated in ESO as compared to other MMOs. All content stays relevant and so do all the rewards. Sure, there is some flavor of the month around, but generally nothing ever becomes completely useless and sometimes old sets have a comeback. Elfbane for example is one of the oldest sets in the game and now it is best in slot for magDKs.

Cut, Copy, Paste are a developers best friend.