You forgot to add (with your classic deceptiveness and sneering approach, that is visible both here and also in DPR) that the "ten to one" ratio is of course fueled on by the cheap-as-dirt 1.6x Rebels, the 1.5x D40s, the D60s, the A200s, the A300s, the 2.0x lower-end 4/3 products, the 1.7x Sigma products and a variety of such mish-mash formats,
Wow, you accuse me of a sneering approach and then describe mainstream DSLRs with words like "cheap-as-dirt" and "mish-mash"!
Stripping the insulting language aside, what you are saying is something that I completely agree on: that cost is a major reason for the difference in sales volume. I have never hidden that at being a major facto, so I do not see why you accuse me of being deceptive. Perhaps it is more precise to say that price/performance balance is the reason: the great majority of SLR users find that the mainstream DSLR formats can offer high enough quality that any improvement from going to 35mm format would not be enough to justify the substantially higher cost.
And the cost gap applies not only to the "cheap-as-dirt" models you mention: for example, even the good quality, well built models at the top of the Canon EF-S line continue to cost substantially less than Canon's cheapest 35mm format option. Even Canon, overall the most aggressive promoter of 35mm format DSLRs, has not managed to get it down to a price vaguely close to what most SLR buyers find worth paying.
In case you are confused, I am not at all denying that 35mm format has an important place towards the high end of digital photography, and in the bottom line for Canon and Nikon. I am only skeptical about the persistent prediction that 36x24mm format will ever get close to the dominance it had in the film era, when the lower resolution and lower sensitivity of chemical emulsions compared to electronic sensors forced the use of a larger format than with digital to get comparable image quality.
P. S. Being old enough to remember $300 was an above-average price for a (film) SLR, it is strange to read any DSLR described as being "cheap-as-dirt".