While search could be better, Google's results for text are good enough. How much better could text search get? Is it possible for someone to build a search experience so compelling that I would want to switch? And even if someone made a new, compelling search technology, could they get advertisers to switch over?
Actually, I don't think there's any upper limit to how much more relevent you can make text search. You could have an AI that directly answers your questions based on the knowledge it's gained from processing the entire net, with references supplied.
More easily implementable, you could have something that cross references a knowledge base such as Wikipedia (or just analyse the content of articles themselves) to split results into relevent categories, eg, Paris the city and Paris Hilton. Or, more tricky, one that I faced today - Flash Reflection, which could mean either a graphical effect or runtime type information.
What about reddit style voting? Google tried this, but I'm sure that ranking results by some measure of searcher satisfaction would be a great way to cut out duplicate/spammy content. Pagerank isn't.
I'm sorry, but calling it "good enough" is more of an indicator of lack of imagination than the merits of Google search.
