I love Warren Spector, but I (sadly) disagree with him on this keynote. Spector said that "we need to embrace mainstreamers who love what we love, not fear them." I do embrace mainstreamers who love what I love.
The problem is that the mainstreamers Warren is talking about DON'T love what I love. I don't geek out over games just because they are games. I geek out over games because they are about things I love - fantasy, science fiction, military history, adventure. I also geek out over other products that are about these things, like fantasy movies, science fiction books, and comics. I do not geek out about, say, indie drama movies, romance novels, and political cartoons, even though they share the mediums of things I do geek out about.
Warren is fundamentally confusing the medium (games) with the culture (escapism/speculative fiction/geek). "Geek culture" hasn't achieved a victory because the mainstream plays games. All that's happened is that mainstream culture has co-opted our favorite medium to deploy in support of *its* culture.
There might be incidental benefits if through exposure to gaming, the mainstream is exposed to cultural content that it otherwise wouldn't have been (Halo, CoD), but it's more likely that we are looking at a future where the AAA games are the equivalent of chic-lit bestsellers, while the sci-fi/fantasy/action games that we love are relegated to the back of the bookstore in the genre section. And that DOES suck.