I won't call it dead, but it is declining. Their various sources of traffic are now regurgitating Wikipedia Content (and other 3rd party sources) via uncited/unlinked AI "blurbs"...instead of presenting snippets of Wikipedia contents with links to Wikipedia to read more.
It's not the only reason their traffic is declining, but it seems like a big one.
I may be wrong, but I don’t think the people that edit Wikipedia are the same people that are content with half truths from LLMs and thus no longer visiting the site. So I kinda doubt it matters much.
Also, Stack Overflow is a commercial website, while Wikipedia is a free (as in freedom) project. Editing Wikipedia feels like you're contributing towards "an ideal", that you're giving back something to humanity, instead of just helping somebody else getting richer.
It's not the only reason their traffic is declining, but it seems like a big one.