Why are ATI cards so expensive now?

I was looking to upgrade my GTX750ti to a R9 NANO the form factor is right and it would be a marked increase in performance,,but the prices are insane.

Even the rx550  is more expensive and offers no performance increase.

I prefer ATI cards, but i feel like i'm currently being forced to to purchase a Nividia

ATI card have always been a tad more expensive and i have always felt they were worth the small increased price difference.

But now,, they seem to be way more expensive.

So why are ATI cards so much more expensive now?