Destroying bits is so darn easy, that people do it too much. I don't delete emails (my spamfilter might delete, I don't). Once in a while it's nice to see what you were up to 5 years ago.
My personal homepage is still running. I haven't updated it in many many years, but it still there. Occasionally my friends and I check some photos from there that I posted almost 10 years ago. And I regret that I have deleted all previous version of my homepage.
And it was a sad day when GeoCities was taken offline.
Sure, if keeping your site up and running (even in read-only) costs too much, it's ok to shut it down. But please, try to save as much of the current Internet as you can so our children can see its history.