I have a different explanation:

Diminishing returns.

A 100% successful StackOverflow SHOULD show a tapering off of questions. This is exactly what we should expect from perfect success. Now, I don't think perfect success is what we see, but a system where a question can be answered once and then re-read many times should absolutely not keep new question counts high, that would be a sign of a massive failure.

The view counts is harder to explain. I would guess it can be partially explained by search engines inlining stackoverflow answers into the search results so people DO get answers from SO, but don't actually go to the site.