Oh, the SHAME!
Dragon fruit became a fad on the West Coast of California several years ago. They were probably always around, but had previously been rare. When they inexplicably became more popular and common, they did so down south first. Their popularity migrated to the Santa Clara Valley a few years later. It probably will not go much farther though, since they are sensitive to frost.
It is not a bad fad, at least relative to most others. Dragon fruit, which is also known as pitaya, happens to be very easy to grow and propagate from cuttings. Locally, it needs protection from frost, but no more than other popular tropical plants. It recovers from minor frost damage quite efficiently. Pruning scraps can be rooted and grown as more plants for friends and neighbors.
Of course, I dislike fads. I am not impressed by the fruit, which might lack flavor…