Two of the things which drive the market are: what people want, and what the producers want people to have. In an ideal situation, both forces come together as the same.
Long ago, I worked part-time for a dept. that transitioned from revolvers to (gasp!) autos. We didn't want them, for the most part, but they made such a compelling offer (armorer support & training, spare parts, transitional training, outrageous pricing were all part of the package) that the bean-counters convinced the Town Board and Chief to give them a trial period. The producers wanted us to have their product. Once the transition was complete and we all began carrying the new-fangled things, individual Officers and many Locals all started to consider them a viable choice for personal purchase. The "market" then wanted what the producers had to offer. Once sated, the producers offered variations, based on words from the street or ideas from the drawing room. They produced, we bought, we wanted more. To justify these changes, they are called, "improvements". Are they needed? No. Can they be justified, and they truely do anything better? Probably. Could we do without them, as mass-produced incarnations of an earlier model? Yeah, I think so.
When all the makers offer their version of the same thing, something is changed. We somehow find a niche for it, covince others to try it, and it becomes fashionable. The cycle repeats itself regularly. The earlier examples I remember from the category of micro-compact (at least that's what they were called then) pistols include the Seecamp, Walther PPK, and the Devil. Very small following in that time, but worth a small mint today.