From a cursory glance, would you say these are still issues people run into? Aggregating these initial questions and the amount of activity they generate up until this day should tell us much about the progress and stagnation of certain programming languages/libraries/frameworks/else and their usage barriers.
In most cases, yes, but I don't think it implies stagnation. With the exception of the CSS ones which have been obsoleted by modern flexbox, those questions are mostly basic enough to defy change:
php: check if an array has duplicates
Java: what's the big-O time of declaring an array of size n?
I agree, plateauing may be more apt in this case. I wonder to what extent exemplary questions like these remain universal, or have an expiry date that just isn't known at this time.