Ask Sony. People are still buying PS2's and it's nowhere close to the XBox in terms of horsepower under the hood. The games are always the thing, and there are never any good ones until the console's been out a year, IMO.
I love my PS2 but I do think it was a special case. I think when it came out there wasn't any other choice really. They also started way, way ahead of the other companies.
Now that the market is tighter and real competion exists I think we won't see another situation where a console sells so strongly based on name recognition alone.