There are some studios that flat out don't allow isolated scores. Paramount I think is one of those. And it's a lot of work AND usually carries some legal components (repayments, contractual stuff, who knows) with it, which is why most studios just won't clear them.
And let's be honest -- it's not a feature that appeals to a lot of people.
It's weird, but it seems to be the case. I think it goes beyond people our age who grew up on those movies though -- we're talking older. Awful lot of elderly or near-elderly folks just seemed happy to watch Harrison Ford again, judging from the (few) places where you see people actually say good things about it.You'd think people old enough to have "grown up" on the first three Indy movies would have hated Dial Of Destiny MORE, not less.
Either way, there's no accounting for taste!