Saga Legends do sell. They're not going to disappear as soon as a case is opened because they have a different market, but, with a few exceptions, they don't hang around forever. It's easy to think they do when you're looking for something else. These figures are easy money for Hasbro and allow them to spend more on basic figures.
They definitely need to revisit their figure selection process.
I ahve speculated that cases of Legends cost less than other figures, making them more attractive to retailers. That may be why retailers seem to like them so much.