Low sales isn't interesting in itself -- the Golden Ring of retail is a low volume/immense markup business. 244 years of history should also hint at the fact that pricing isn't the issue.
No, it simply hints that pricing wasn't always an issue, not that it isn't an issue.
The quick way to find out is - if they could make a good profit selling the entire set for $x where $x < $current, would they still be doing it? The answer is yes.
The reason the price used to work and doesn't now is that digital equivilents are not only (subjectively) better/easier/etc. - they're also cheaper.
