Why they're not popular in the US is obvious.

What I don't get is why they weren't popular in Europe. Especially before roaming rates were put under state price controls. There are places in Europe where people commute weekly or even daily across national borders and have different networks to deal with. Dual SIM phones seem like they would have been no-brainers.

But the only place I saw them were in Singapore and they were universally "chinaphones" which were cheap knockoffs of the iphone and didn't work well. I'm amazed to see the Moto G dual SIM phone, thanks for pointing that out!

Hm, there are places selling them in the e.g. http://negrielectronics.com/motorola...ked-black.html however it seems they have band 8 (900) instead of UMTS IV (1700AWS) which means they won't work with Wind or Videotron in Canada (but will work with Rogers) and might not work well or work very fast on T-Mobile (But should work on AT&T -- as much as anything does)