They could be several things. If they are supposed to be hardy where you are, that eliminates a few of them.
I would do several diff things with them, since you have an abundance. Hopefully one of the treatments would result in blooms. That would increase the speed of your investigation by up to a few years.
Having been confined in a pot might be causing the bulbs to be more flat than a same clump in the ground.
If hardy, keep this in mind:
Surprise Lily (Lycoris squamigera)