Unfortunately I'm sure the disney guys are looking at the numbers for copies sold when it comes to non-new release movies and they're pretty brutal

(http://www.the-numbers.com/home-market/bluray-sales/2014 )

I'm sure Star Wars '77 would be a cut above most catalog titles and do fine, but when deciding what kind of money to spend on it: a pricey full restoration vs. a basic catalog treatment, which would be almost all gravy, it's easy to see which path they'd rather chose. I would love to be wrong.