I almost never see anyone carrying a Micro 4/3 camera in the US. Micro 4/3 cameras haven't, for the most part, made it into large brick & mortar retailers like Target, Walmart, Best Buy, although I recently saw that the E-PL1 was selling in Best Buy.
Costco, a big, big box warehouse store, has the E-P1 now, and I know they did have the E-PL1 and I only know that because I get periodic emails from them. As we all know, the issue with most of these big stores is that unless someone has already researched their camera choices, they're not going to learn anything from the salespeople at these places.
I have only seen two m4/3 cameras in Puerto Rico: my own E-P1 and the display E-PL1 at the Best Buy in San Juan. I seriously doubt that they have sold any.
There are no dedicated camera stores in Puerto Rico, though. Except for my Canon EOS Rebel T1i which I bought at Costco, every single camera, lens, and accessory I have purchased in the last 20 years has been bought sight unseen via mail order.
I'm the only one among my friends who's either a Loomy Goofy or Oly Epi. Everyone has dSLRs. Most people that stop me have never heard of M43. Japan will always champion smaller cameras. Miniaturization is an art form there, most often out of necessity. There is just so little room there.
What makes you think that? From my own experience (Canon 40D owner) I certainly was more than happy to "trade down" to my EP-1 (though I certainly don't see it as that, I see it more as a lightweight alternative) because I was getting fed up with lugging the Canon (and especially the lenses!) around, especially for travel and general purpose photography. That's not to say I don't still use the Canon - when I go to motorsport events I do still take it with me as the Pen isn't really a sports camera - but for everything else it's the Pen all the way because the image quality difference is negligible for the type of photography I do, but the weight advantage is crucial.
I also know there are others (certainly I've seen people posting on mu-43.com and other forums) who have done exactly the same as me, probably for the same or similar reasons, so I don't think it's that uncommon for those who already have a DSLR to buy a smaller but similarly capable camera like a Pen or a GF-1 as well.
My first m43 the G1 was hard to come by with the one kit lens, I later added the 45-200 form USA (no stock here)
After that I acquired the GF1 with 20mm from Hong Kong (no stock here with weeks wait)
All my lenses subsequently came via Japan online store (Ebay)
the PL45/14-140/7-14/ and the PL14-50 stock here was hard to find or pricey, I saved close t0 1/2 from Japan Ebay.
I wanted to go Oly so once again I headed to Ebay and got the E-P2 first and followed with the E-PL1 (not in stores yet at the time)
Recently the E-P2 was $1000 AUS way above a twin kit low end DSLR offered price is the thing here for most people and the twin kit DSLR wins
Seems not enough push here for m43's unfortunately so stock and lenses always low
Here in Aus. the DSLR's Canon, Nikon and Pentax dominate in sales and advertising.
The low end DSLR's with cheap kits lenses get the most push here and they offer appealing value for money.
The 2 largest camera stores in melbourne when advertising in the newspaper rarely show m43's but today the Sony NEX get big honours.