They replaced all of the dead palms last summer and I passed them when they were all wrapped up without extra heat this winter. Here's what they looked like a few weeks ago.
As you can see, results may vary. Even among the same species in the same location with the same protection.
I personally wouldn't want to keep spending money replacing large dead palms, but I do enjoy seeing some of them pull through. When wrapping an out of zone palms without giving additional heat, washies are very reliable survivors...at least in Oklahoma.