I don't know why you're treating them as mutually exclusive. Single points of failure are as bad when it comes to organizations as they are with anything else. Internet Archive (the org) could stop existing with the flick of a pen. I don't think “Let Somebody Else Do It” is a healthy attitude to take, and I'm going to keep doing what I'm doing.

Plus for as great of a service as Wayback Machine is, it can be very unpleasant to actually browse. I dislike how it injects its own toolbar into every page (yes I know how to massage the URLs to get the raw page data, but it isn't browsable that way). Have you never encountered sites in Wayback Machine where certain pages were just randomly not archived? Or when you click a link and get a page from years earlier or later than the one you came from? Never encountered a page or an entire domain that was blocked from Wayback Machine? Why do you think I would get started doing something like this in the first place if I didn't find it more fun to browse my own archives than Somebody Else's?