It’s basically a story of a product which appealed to a small counterculture riding the wave of that becoming mainstream with a commodity product which got to keep the weird in a way which didn’t offend the sensibilities of the median culture.
In other words they very gently sold out without sacrificing much.
https://web.archive.org/web/19970131094107/http://kingarthur...
The bottles I buy still are
As for what makes it so good? I think its a combination of it being REAL soap and not some alternative amalgam of desurfecants and that they don't remove the glycerine. Sure, it makes it so you can't use it in handpumps (gums them up) but its also why their soap manages to clean so well without drying your hands out.
Lastly, the use of essential oils for the scents just makes it a luxurious experience.
All they had to do was get it in front of more people. anyone who tries it gets hooked.