I think you're being a bit hard. Its a Sunset z13 area that they call "subtropical desert". I think its gotten even milder since that was written 30 years ago or more. Those two palms are far from clinging to life...they are thriving.
There was an article that quoted the Mayor of Phoenix who said that the desert had become warmer in his lifetime and that they are expecting the first ever triple digit low soon,and how they are preparing for that killer heat.
All that is just perfect for Coconuts. AND, we talking a large,large, area...not just one or two homes. I don't see much protection given to the Palm Desert beauty- and its huge.
When pro landscapers see that Coconuts are now growing in the low desert? You can bet they will be planting them in front of Hotels,Casino's (Indian),maybe public buildings...and planting them large from Mexico maybe? I bet.
When I saw a tropical Papaya in Hayward,with large fruit,that's a huge example for our record mild winter..and it could always be milder. I just hope wetter too.