If he wants to delete his old blog, it's up to him, he isn't accountable to anybody. Don't punish people for posting quality material on the internet.
What solutions are there? There are a few. My favorite so far is for Scott to restrict access by LW karma, which would allow him to maintain his privacy against the web, while still not denying those brilliant, humorous, and insightful posts to those who would truly appreciate them.
Are you willing to fork out the money to hire a programmer to implement something like that? It's not trivial at all.
Also, Yvain's policy of reposting worthwhile stuff to his new blog seems like a very sensible solution to what you're complaining about.
I actually agree with you: He is under no obligations whatsoever. None. But I still am allowed to plead my case to him, for him to decide as he wills, and to spread the issue and discuss it so that the best possible solution can be reached.
As to programming something like that: I am willing to personally implement something like that if asked, although I was more thinking of the manual method of those who want access PMing Yvain or his designated representative and asking for access. Again, I am willing to have the burden of such a task placed on my own sh...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.