My 750F1 was a similar deal. A basement queen for most of its life and then put on eBay. 600-odd original miles on the clock. My dad snatched it for $5600, then sold it to me.
Most of the value is in the low-miles, but I am not of the mindset to buy a low-mile vehicle and then not drive it. Basically you have a REALLY expensive model at that point. I'm gonna ride the ever-loving crap out of this thing.
Think about what a new bike costs. I basically am getting a new bike, that I would argue is more over-engineered and over-built than most modern machines, and at a fraction of the cost. It does need a few piddly things, but it's stuff I can do over a weekend.
When I get home, I need to do the 600-mile service. How cool is that, that I can say that about a 31-year old machine?