Lorn, I think we all learn to grow those plants that do best in our zones/climates. I for one couldn't take all of that extended cold. Most growers here are focused on those plants that do best and need not to be coddled.
Normally I would cover my large potted lilies with some plywood but I didn't do that this year. Then it got done to zero, snowed, then rained. I did wrap a couple of large pots of strelitzias with a large comforter but it was of no use under these conditions. I had babied them from seed 5 or 6 years ago but I could never get them to bloom. Now I have another 2 large pots to fill with *something*.
The gardens that really took expensive hits were the tropicalesque ones. On my daily walks around the neighborhood I see "hardy" bananas melted down and essentially done for and palms totally dead looking (probably are).
Joe is right about the LAs. They are first to poke through.