Also - the cost of servicing that marginal niche is now so low that it's economically feasible to build a solution just for them. To use the kitchen example, most people want gas & electric ranges, but a few might want eco-friendly solar-powered cookware. This product doesn't exist (to my knowledge), but it's because the cost of designing, tooling up, and manufacturing it is above what people are willing to pay. In software, a niche solution could probably be coded up by just a couple programmers. It'd have more economic value than the code they wouldn't produce at their day jobs, so it becomes economically feasible.
Actually, it's probably because no one knows how big that market was. If you produced market evidence that there were 1 million people that would buy a solar powered stove in the next year, there would be product rolling off assembly lines in less than 6 months.
Read Seth Godin's book Permission Marketing if you want to learn about market creation and demand-driven design.
