[LoganCale]

They're growing in popularity, but they're expensive and some of the popular ones (not PLBs specifically, but satellite trackers & communicators) like SPOT and DeLorme inReach have monthly subscription fees as well. Someone who isn't out alone all the time may not feel they can justify the cost.

I carry an inReach and find it fantastic. I've never used it for an emergency (though an emergency leading to a late-night Air Force helicopter rescue of someone in my hiking group several years ago prompted me to purchase it) but it's fantastically useful for text communication with friends and family in areas with zero cell reception, as well as (very recently added) weather forecast downloads for your precise location. And in the event of an emergency, being able to communicate details about your situation is very useful sometimes.

[Tiksi]

You can also rent a PLB/sat communicator for relatively reasonable prices (<$40/week) if you only hike occasionally and owning one and paying monthly wouldn't make sense.