Nexus 4 and Nexus 7 (the latter one being a mini tablet) were the best mobile devices I ever had. They worked well together and on their own. Combined with a real laptop and smart tv I really had all the sizes I could ever want to have.
The problem, I think, is not that nobody wants tablets but that there simply isn't a good one to buy anymore.
It was almost as bad or worse than phones... updates were less frequent and today it's hard to tell what's new or old anymore... On Amazon I see everything from Samsung Galaxy Tab S2 etc. And nothing seems to have anything newer than Marshmallow on it.
Google started selling "premium" devices, leaving thier middle/value segment behind, and Amazon's Fire devices are at the low end running 2012 spec hardware. It's hard to be enthusiastic about it.
The problem, I think, is not that nobody wants tablets but that there simply isn't a good one to buy anymore.