The stove industry was all cast iron foundries making parts that were bolted together. Bob Fisher is credited with welding steel plate together making a stove much more air tight than stoves at the time. (others may have existed, but they were not patented or mass produced)
He was a laid off welder, who wanted to make his own stove, and when it worked very well, others wanted one as well. He started selling them, and his place of employment closed down, helping him make the decision to go into business for himself. With a few employees, he couldn't make them fast enough, so he taught industrious type people how to make them. He sold them a license to build with plans of the different models, giving them a protected area. He wanted the builder to make the money making the stoves, and get a small cut himself on each one sold. Stoves were fabricated in the shop in the rear of "Factory Showrooms" where they were sold in the front. This allowed custom builds with the sales staff in direct contact with the builders. So he could keep track of what was owed in royalties, and he would know what was being made, he had doors cast at a local foundry. Each fabricator would order the doors from him they needed, and pay the royalty fee and door cost to him. The doors were shipped as needed to his growing licensees nation wide as well as Canada. The doors were highly protected.
Unfortunately a few licencees started making their own version of his stove. Some lost their license, others were sued, and these builders started other name brands that originally built Fishers. Most stayed loyal to Bob.
There was a time years later when they were 60,000 stoves back ordered. Hesston Mfg. in Hesston Kansas was contracted to make stove bodies to catch up. They sent bodies out to fabricators without doors. By then more foundries were making doors across the US to save shipping from the West Coast. As he found out about others copying his stove, there were too many infringement lawsuits to mention, so they decided to simply make the best with more accessories and models than any others. At 1.5 million stoves at the time, they made more than all other manufacturers combined.
Fisher was a unique company.
Whirlpool made the gas conversion kit for every manufacturer of gas appliances when I retired from the propane heating industry. No matter what brand, gas parts are marked "supplied by Whirlpool Corporation".