some points:

Result quality has not really improved, all the while: more and more content is in silos that are not easily searchable. Spam/SEO/trust in content remain a problem, thus many people rely on social recommendations for content (which has its own problems). More and more content is in non-textual forms. Google (sometimes vastly) prioritizes content on their own platforms.

It's not. Search works great. I think that's the wrong way to frame it as being "stuck." Better to say where's the opening? The main one that I see any action around is privacy. There must be other opportunities that nobody's seen and acted on yet but will. It'll be interesting.

I suppose you are too young to have used Altavista? Or Yahoo "curated" link lists?

The pre-Google search engine I preferred during it's brief period of utility was 'WebCrawler' because it returned dumb results. Google doesn't do that any more, it's back to curated links with advertising being a large factor in curation.

Oh god, I remember how exciting it was when Google rolled out. Goodby Altavista and all the rest. Though I do have a place in my heart and gratitude for Altavista. That search engine found me whatever I wanted to find. It worked well. Google just came in and was better.

My memory of Altavista was that it was great for discovery of obscure but interesting sites. Sure, you might have to go through 10 pages of results to find one, but the experience was one of serendipitous discovery. It's lack of precision (in favor of recall, making it seem less winner-take-all, SEO-optimized) seemed to correlate strongly with the notion of "surfing" the web. (And the use of the phrase "web surfing" likely declined as Google, and later, the app economy, rose.)

Yes I have not used altavista but I have read about it, and I've read the book and I know search was stuck back then, my question was why the above comment says search is stuck at the moment, because I don't see search stuck at the moment.

I am not the OP but I interpret "research is stuck" as follows:

Remember Altavista (and similar search engines from the era?) it worked, but everyone was using the same approach so you got the same results when you searched for a given word... Then Google arrived and the quality of their results looked like magic.

In terms of "user experience" today does resemble then: Bing, DuckDuckGo... They return a subset of what Google finds, not something qualitatively better.