The funny thing is that there is one major reason why I don't see bing taking a substantial number of people away from google, which is that on the whole google does what it should do, there isn't enough dissatisfaction with google to get people to switch in droves.

When google took on altavista pretty much any single keyword search on altavista was 50% or more spam.

That single item is what gave google traction. They didn't spend any money on advertising their service, it just worked, and so much better than the competition that if you had tried it once you were sold.

I don't remember any 'altavista side by side with google' comparisions at the time that gave you the impression that it was too close to call.