[edit] Quick clarification: The OP compared Nokia to Apple and Android, so my answer was specifically about Nokia smartphones. Nokia feature-phones have always had a decent market share in the US, and I think that the average person in the US thinks of those feature-phones when they hear the word Nokia, and has no clue that the E or N series phones even exist. [/edit]

I live in the US. I've never actually seen a phone running Symbian in person. The only Nokia phones I've ever seen are feature phones. I don't just mean I don't know anyone that has one, I've never seen one in a store when shopping for a cell phone; of course I don't own one!

I work at a tech company where probably about half the people have smartphones of some sort. Until the iPhone, that meant something from RIM or Palm/Treo.

I would bet that the cell phone providers are primarily the ones at fault for this, but I'm not sure. Verizon is the largest Cell provider in the US by a large margin, and I understand they have all sorts of requirements if you want your phone to work on their network.

[edit] I just looked at the wikipedia page for the nokia E series and N series, and notice they are GSM only. I've only ever been on CDMA (and AMPS) based networks, so that explains a lot right there.

Here's an example of what people in the US think of when they hear "Nokia" it's the Nokia phone I've seen the most, with the possible exception of the old monocrhome candybars:

http://en.wikipedia.org/wiki/Nokia_6255i