Supply and demand in this case doesn't accurately describe quality, only utility - perceived satisfaction. In other words, someone who knows nothing about mechanical keyboards but likes shiny glow in the dark crap with tons of unnecessary buttons will be more likely to purchase a fancy Logitech rubber dome "gaming" keyboard at >$100 vs a plain mechanical at <$100. That's why historically Logitech sells a lot more rubber dome gaming keyboards, vs lower end mechanical. Companies sell whatever people are more likely to purchase, whether or not it is the superior product.
In regards to sales, I've seen that people will purchase inferior products at HIGHER prices in both my own company and from working at others, because they are already convinced that what they are buying is better without even trying the competition. For example, take phone systems. People purchase inferior key systems at higher prices that do less and cost more than voip, because that is what their business owner friends are using. I will make an effort to explain why they should go with the lower priced and higher quality solution, but sometimes they still want the inferior product. They both essentially do the same thing, produce dial tone, but lack of knowledge or want of acquiring that knowledge prevents them from making the better choice. Because they hear about choppy calls from their friends who also own businesses, they prefer the higher priced model that does less but is more "reliable." What they fail to understand is QOS or a second link(which you would pay for with a legacy system anyways) can avoid choppy calls. From a sales perspective, it doesn't make sense to argue with the customer if the legacy system has a higher profit margin anyway.
Right now the perception is that the 45g is the better product, and that 55g is "too heavy" for most people. This is because more people already own a 45g, not that there are tons of people who hate their 55g and told everyone else how much it sucks. People assume that because the 45g or variable feels good to them, adding an extra 10g could potentially ruin the great feeling. Therefore, having tried neither, a person would be much more likely to purchase the 45g, and be happy about it. The 45g owner will tell everyone else how great the 45g is without having tried the 55g, and more people will buy a 45g. It doesn't make sense for a company to push the 55g even if it is superior, because the 45g pretty much sells itself. It makes more sense to produce what people are more likely to buy, regardless of quality.
