Never mind them going bust in ten years, in a year or two they'll redesign part of the site again and lose it anyway.
For example, a while back they managed to lose parts of my profile (something to do with "pages" I think), and I used to be part of a group for my year at high school which, as far as I can tell, has silently vanished.
They need to sell/provide an annual "yearbook" via shutterfly or some service automatically. Say $50 per year and you get a physical book with all your timeline info and experiences each year. with a fold out tab/page at the beginning and end so you can physically connect the books together side-by-side each year to flip through. As well as a DVD.
Sure many people will spend time curating their timeline, but I think that for most people an algorithm will just select the best stuff.
Nobody is stopping people from continuing to scrapbook, but let's face it, not many people do that anyway (I know that I don't). Now, with 0 additional effort on the user's part, he or she will have a digital scrapbook. I think that's pretty cool.
I just downloaded an html version of facebook profile before deactivating the account. It's got almost all the content you could call yours in it and it's presented in an easy to use way. You don't get everything, but it wasn't nothing.
You spend an afternoon "scrapbooking" in real life, and you get something that your grand-grandsons might, one day, inherit and read in awe.
You spend an afternoon scrapbooking on FB, and in ten years FB goes bust or whatever (Geocities, anyone?), and you've got nothing.
I guess the real test will be my wife -- she loves scrapbooking.
(this, and the first time I went through the presentation my brain was screaming MYSPACE really, really loud.)