It's an offhand line but the point stands - people who have the resources to overcome the barrier have tried and the phones don't sell in great numbers.
Once they get used to a good soft key board like you get on the iPhone or most Android phones people either don't want (or don't feel they need I suspect) physical keyboards.
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.
That form factor is fine, although not popular with consumers. I had a Droid 2 for a while, and found myself using the soft-keyboard more and more, particularly while not using connectbot.
I had one of the first generation Droids, and much preferred that form factor to any later smart phone I had, largely because of easy access to keys normally hidden behind layers of menu.
The problems I had with it were primarily related to build-quality I think. The 'i' key wore out after several months for example. I think these problems could likely be fixed by not skimping on the parts, but who knows.
This is incredibly disingenuous because of the high barrier to entry on cellphone manufacturing.