Well, I'm in Sweden on a gigabit connection right now. Quite a few countries have good cable and cell infrastructures. So, "other countries" might generalizing.
I was about to say the same thing. I live in Thailand and haven't had any issue with slow websites (besides the usual borked connection every now and then). I've worked for two different companies here that rely heavily on the cloud for extremely operations and both selling cloud-based software (both are SMEs are targeting SMEs).
Now, I don't even think the overall quality of internet connections is that great in the US and I'd say most European countries do a better job overall (less disparities inside individual countries, not among all European countries).
The US is not particularly known for fast internet connections, a few localized exceptions aside.
But yes, file size must still be considered. 3G, bad reception, congestion, spotty wi-fi and loading speed (spdy isn't that much faster) are very real concerns.