Let's face it, in the US, the first that pops into people's head when they think of "Android" is THE Droid. By Motorola, on Verizon's network. Apple targeted the bastard child, the Eris, in its antennagate fiasco, but no one cared and instead looked at the Droid X. A Motorola product.
The Droid and Motorola got the most exposure last October and that's why it's so far ahead today.
That isn't to say anything about the DInc. Internationally, it is more or less the Desire and it's doing well in most countries. It's just the US has their eyes set on Motorola products.
Face it, who's the biggest carrier? VZW. I rarely see Sprint adds or T-Mobile ads anymore. GayT&T seems to have died off along with Luke Wilson's career. It's VZW on TV showing off the Droid X. I saw only two or three DInc commercials ever.
I blame it on VZW's decision to use the "Droid" moniker for every Android phone they have. It's stupid and seems to have subconsciously brainwashed the public into thinking the Motorola products are better or simply the only ones VZW has.
I have a Moto and love it. I think it's unfair to the rest like the Ally and the DInc to sit in the shadows.