Well, that's like saying we should destroy the original tools cavemen made because they aren't of any use to us now. The point of Geocities in current day and age is to show us where we came from, IMO.
My point wasn't about what we should or shouldn't do, it's about what we should expect a company to do. The original point was, "Yahoo is willing to destroy Geocities" -> "Yahoo is willing to destroy Delicious". And my argument is that Geocities and Delicious have a fundamental difference that would probably make people complain harder, and thus make Yahoo think twice.