Getting yourself an SD card is pocket change. As I mentioned to someone else, DQ1 and 2 come on a single card (up to 32gb) and that happened to be up to 3000 yen more expensive than the likes of Zelda and Splatoon. (for reference, DQHeroes is 9500 yen on the eshop) Capcom clearly want to avoid a high price, which in turn would impact the digital prices of both games since they would need to be priced evenly to reflect the physical release (or at least close enough)

The aren't saving costs. They are trying not to lose money. A 16gb cart is already higher in price than a 25gb PS4 blu ray. So a 32 GB is even more expensive. And both RE1 and RE2 combined are 39GB. So it's either an even more expensive 64gb cart or 2 different carts. Both are significantly more expensive for Capcom, and therefore for you too.