I suppose that John's business model for his hobby shop was to create sort-of a three-legged stool: the seat being a regular walk-in hobby shop and the three legs being the mail-order business, the Fly-In, and the museum. These days a regular walk-in hobby shop just doesn't generate enough traffic to survive. But a mail-order business is not cheap and easy to run when economics of size are not on your side (you can't have free or low-cost shipping unless you are Amazon or Wal-Mart). So, how do you get people to drive over 4 hours to get to your hobby shop to buy stuff? Stage a Fly-In, of course! But that only covers one week of 52. So, how do you stretch that effect throughout the year, at least a little? One approach might be by opening a museum: that way you can get at least a little bit more traffic for your hobby shop.
This may not be the best solution for survival of a hobby shop, but it did work for John. With his passing and cancellation of the Fly-In the business model fell apart. It looks like someone realized that it needed re-assembling.
Caveat: I am guessing from afar on all of this. I don't know if John had a written business plan like this or that he even discussed this strategy with anyone. But it does seem to be what he was trying to do. And I hope they succeed as America needs at least one really great hobby shop.