Forest Service fire lookout towers

I'm not quite sure I understand the status of the Forest Service fire lookout towers nowadays.

Originally, these towers were built to be an early warning system, to try to learn about wilderness fires as early as possible. Here's a nice page: Fire Lookouts. The fire lookout towers had clever techniques for helping the rangers determine what they were seeing:

Osborne first invented a "firefinder" in Oregon in 1911 using a rotating steel disc with attached sighting mechanisms. This instrument allowed lookouts to accurately pinpoint the geographic location of forest fires by sighting distant smoke through the device. Further modifications and technological developments were made by Osborne to the firefinder over the next 30 years. The Osborne Firefinder was widely used by Forest Service lookouts throughout the 20th century, and production of the devices by various companies continues even today.

But my understanding is that much of the wilderness fire observation duties is now handled by satellite photography, meaning that many of these lookouts are no longer used. In fact, I understand it is now routine to rent a fire lookout as a vacation cabin.

But my son, who recently returned from a glorious camping trip at French Meadows Reservoir near Lake Tahoe, took a day trip up to Duncan Peak Fire Lookout Tower, which is most certainly not closed.

In fact, while Dan and his friends were getting a tour from the ranger, who graciously took the time to show them the (still-in-use!) Osborne Firefinder in the tower, as well as the carefully labelled sight lines from every one of the windows in the 360-degree view, the ranger was actually tracking two separate fires.

These are not Dan's pictures, but they show the lookout very nicely: Duncan Peak Fire Lookout Station

So, what's the actual story? Are they phasing out these lookout towers? Or is this still How It's Done?