It isn't as popular as ever, at least not in the Western world. I don't know what your frame of reference is, but it is positively non-existent compared to a couple of decades ago. Approximately zero kids, give or take a few, put one on their Christmas list, where when I was a kid it was many kid's dream item. I would say the most common buyer today are middle-aged men who buy it just as a thing to own because they remember how desirable they were when they were in Scouts in their teens.

>A tool of "last resort" seems to miss the point

It is quite literally a tool of last resort, and in practice people who actually own one (such as myself) have often never, ever actually used any of the options available on it because they're terrible options and we always have something better available.

Like a legitimate folding camping knife, which we all have in our camping supplies. An infinitely better knife. A tiny multi-screwdriver kit. The Leatherman brand went big by making a legitimately good, well constructed pair of pliers that they add some "in a pinch" options.

Serious campers who portage and go deep country have a proper assortment of gear and never lean on their SAK. The rest of us usually get there in a car and have a...proper assortment of gear.

But again, if you're in a situation where you have to use one of the tools on a SAK, you probably screwed up and it's a serious compromise. It just isn't a compelling metaphor for software tooling.