I would say they are the most popular livestock guardian dog where I live, just from roadside observation, but I don't know how long this has been the case. Lamas seem to be in second place.
I never even knew about them until about 10 years ago, then knew I wanted one immediately after looking them up.
Then a year later my sister, working at an animal rescue shelter, let me know that one came in after being abandoned due to running off and being picked up by animal control multiple times, and then I immediately got on the list to adopt.