So right OG. The PNW is zone 7 or 8, I think. At my mother's house in Vancouver, BC she had a very warm, protected south-facing bed where the glads would dependably come back year after year. Other places in the garden, they'd bloom wonderfully, the first year they were planted, then disappear.
So if you want to plant more glads, I'd either find the most protected south-facing area you can, then mulch them heavily in the fall so they won't freeze, or plan to lift them after the foliage ripens off, and store them indoors for the winter. In a raised bed, they are actually a little more exposed to cold, being as the air can cool the beds on all sides as well as from the top.
I'll sheepishly admit that as she got older, I stopped buying glads for Mum's garden, and would just buy the bunches of cut glads from the grocery store. They take a lot of time and effort for the short time they bloom, jmho.
They're also subject to a wide range of diseases, fungal woes and insect pests. Google "Gladiolus diseases" and you'll see. But I think most likely yours just died off from the cold.