I can believe that's all true. So people now primarily consume the content through interfaces that inherently would make it difficult to interact with reviews. (And I suspect if they did pop up a box asking you to add a review after you watched something that would really annoy everyone.)

In a lot of ways, the user reviews are mostly a vestige of when people used them while adding DVDs to their queue.

They didn’t have it in the UI. There is nothing inherently difficult about browsing reviews on a mobile device. Millions do it every time they’re about to download an app. There is no option to read reviews given to effectively 85% of their viewers. That was their design decision. And now they’re citing review usage numbers when their design decisions promoted low review usage numbers. They’re providing a circular argument which implies that it is not the main reason.

It's not at all hard to "interact with" reviews on mobile or with a remote.

Talking about a popup is a non sequitur, it's not like the web site does that.