Most of my lilies simply disappeared over the winter. I had a dozen or more in a 50' x 8' perennial bed (mixed with other flowers). Different colors, Asiatics and others. Some of them have been around over a decade. Most are many years old.

We had one night where the temp dropped below 20 below. I saw no evidence of moles. Sometimes there are a lot of tunnels visible in the yard nearby, but not this year. Every fall I water in mole repellant. Other perennials are fine, delphiniums, poppies, columbine, Cranesbill. But now that I think about it, no perennial dianthus survived. I usually lose about half of those.

Any ideas?

Lilies are especially susceptible to winter wet and the bulbs can rot. --If the ground is frozen (so the water is frozen, too), then it doesn't count. But the ground must be frozen down where the bulb is in the ground, not just the surface. -- Therefore watering in the late fall usually not a great idea. Remember water doesn't drain as easily in cold soil. Dianthus are also more susceptible to winter wet, compare to other perennials. My guess is that for whatever reason, your soil went into the winter more wet than usual, and/or didn't freeze as deeply(?) so water stayed in the liquid stage longer.

Maybe you had some abnormally heavy rains in late fall?
Maybe you watered in the mole repellent later in the fall than usual?
Or watered more heavily?
If you replanted your lilies last fall, this can add to the problem.
you shouldn't be fertilizing, either.

I would suspect with the mass of loss that a tunneling rodent has a chance of being a culprit vole, mouse chipmunk. They can be sneaky.

As Leftwood said, other factors might also be in play. There are a lot of potential problems that could cause no shows. Lilies tend to be very hardy. However it happened, I am sorry to hear you lost them.