#1 It is crazy and I see a toolbar on just about any average user computer. However, most people do not explicitly install them. They're being silently opted-in or gently coerced into it.

#2 and #3 Google is so influential that it's highly unlikely to happen on the current playfield. They either buy a potential competitor out or cripple their business. I can only see two opportunities for this: a) specialized niche search, b) search based on a new disruptive technology.