There used to be an idea of "follow the alpha geeks", that while mass market adoption was a goal, a huge amount ofake or break came down to what the very good, very involved users were up to.

The relevance of extensions has somewhat faded, aside from ad blocking, byt back the day extensions were imo quite important for many, made the web a popular & more lively place. I'd have a number of extensuons telling me other related sites people were enjoying. I could annotate the page, chat about the page. I could easily save the page into my various bookmark services. Extensions made the web social, & helped it interconnect. Extensions interwove the web & drove cool at a critical time of adoption.

Whatever the state today, to ignore the historical relevance of how important extensions were for generating an active, enthusiastic user base, for differentiating: these are not to be ignored or casually cynically written off.