I have thyme and it dies back to nearly nothing most winters. I consider it a short-lived perennial.

I don't have that problem. I have more than enough thyme every year. And I've divided it, moved it and it spreads well too and I have clay/loam soil. Most of mine is in half a day of sun. I have plain old thyme started from seed and I have a Golden Thyme. The golden thyme, I took a little section of one at the edge of a border and planted a patch at the end of all my vegetable beds and now there is so much of it, I'm thinking of taking it out and putting something else there.

A lot of times, after the winter, there are a good amount of dead stems, but that doesn't seem to matter, it just starts growing again from the roots. I trim off the dead stems and that's it.

I don't know why I am having a different experience.

I have similar experience to PM2, with a fair amount of damage some winters, but I cut it back hard and it regrows. I have lemon thyme and wooly thyme and have grown them in a couple different gardens, with both in unmulched gardens in full sun with sandy soil.

I've had very good luck with thyme in my garden. I planted 4 small plugs in a raised bed about 5 years ago, in part sun, I never water and it returns every year. It does look dead in the Spring. All I do is give it a hard cut to get rid of all the dead stems and it grows back beautifully in no time.

It varies a lot for me. Creeping wooly thyme keeps its leaves and looks ok right through the year. A very basic culinary thyme (not sure variety) looks completely dead in spring but I chop it back and it leafs out. French thyme is my favorite for cooking and has never made it through the winter. It may be worth trying a few.