That a large company can make enough money by focusing on one type of phone, thus not splitting their engineering efforts doesn't mean that there wouldn't be a viable niche market, if not for barrier to entry.

I often hear people lament the design of their phone, caused by the preferences of the majority.

It's hard enough to make a profit on popular phones, as evidenced by the woes of HTC, Blackberry and others... making a phone for a niche group, especially if you can't charge materially more (and I mean $1,000 or more, unlocked) just doesn't make any sense. Particularly when you consider that carrier and OEM marketing (large national campaigns, in-store placement, etc) doesn't scale down to small volume products.

Making niche products doesn't work well for consumer electronics in general, unless you can sell that product at a much higher margin. Having a keyboard on a phone just doesn't seem to result in being able to sell it for twice as much.

Another issue with keyboards is they don't internationalize well. So rather than having 1 hardware design worldwide, you now either need a TON of SKUs - one for each country (and you can't move inventory from one market to another) or you need to further limit your target market to just a few regions.