Things like records are meant to be broken. That is a fact. I don't put a lot of faith in this type of record though since we are looking at at least two released versions of the Raspberry Pi and a hell of a lot easier on the pocketbook price point.
Commodore sold as many C64's as they did with a high price point, no Internet to get word of mouth going, and they had nothing but an uphill battle against the computing juggernaut that is known as IBM.
I am not taking away from the Raspberry Pi and its success, just saying that it was definitely tougher to reach #3 in sales back before the Internet.