Well, personally, I have a never say never policy but for sure .com is synonymous with the internet, with all its success and failings, and I believe .com will in a sense always be king. It was born with the commercial internet and for all practical purposes, the internet that most of us know. But i do believe other extensions will come into play, and i believe (but cant prove) the info will encroach upon .coms typin supremacy because it is so common an abbreviation. Honestly, I think .info will be the ultimate niche extension, a very, very strong niche extension, maybe even having more value is some uses than the equiv. .com.
Maybe not.
But they said the titanic would never sink (however, they did get a blockbuster from hell movie out of it) and many perceptions have been shattered to bits over the past 2 years including the seeming omnipotence of the internet economy, the safety of us citizens from foreign attack and even just basic confidence in the future of our planet.
Its all subject to change and .com, powerful as it may seem (or really, seemed) can be subject to change just as well.