@KimW -- Sorry for not replying sooner. I just read your post today.
The boiled method was the method used by all soap makers, large and small, to make soap in the past. It is still used today by medium to larger soap makers.
As far as I can tell, the "boiled" method of making soap is seldom used by the small-scale soap makers I've encountered in person or online. I think some small-scale soapers try a batch or two as a curiosity or perhaps to pass a Guild exam, but that's about it.
It's a time consuming method that works best when there's a large kettle of fat to be turned into soap. That's why the frontier soap kettles were huge cauldrons -- if you're going to spend a day or two making soap, you need to make a big batch to make the effort worth the time and trouble.
People have long known how to make soap using the cold process and hot process methods as well as the boiled method, but the boiled method was long preferred when fats and lye varied a lot in purity and the purity could not be easily measured. Many small scale soap makers today have the luxury of using fats that have a consistent quality and alkalis with a consistent purity.
Boiled soap is usually finished so it is "tongue neutral" (meaning no excess lye and no excess fat) or "sharp to the tongue" (meaning slightly to moderately lye heavy). The soap tends to keep longer due to zero superfat -- that will be especially true if less-than-fresh fats are used to make the soap.
I've rambled on long enough! I have an article and a couple of videos on "salting out" soap scraps, which basically teaches a person some of the basics of the boiled method. Here's a link --
Soapy Stuff: Salting-out soap