Not always, and if that were true it would be industry-wide, not just Samsung
Edit: provided the issue is in fact with CDMA technology
Incorrect. GSM GN is still not officially in the US. If nothing else this is reversed because although it launched later, all evidence of the GN of either variety (in Google's launch videos and Romain Guy's videos) prior to release was of the Verizon LTE one, not the GSM one. The fact that the UK got to release the GSM one first is most likely due to bickering over the terms between Verizon and Google.
But, the point is that iPhone being on ATT first has NOTHING TO DO with anything regarding care for good reception.
Probably true to the first two points, but AT&T was not the first carrier to have smartphones. Unless I have forgotten about some (and other than all-GSM Europe which had some Nokia devices starting in the late 90's), Sprint was actually the first with some of the early Palm and WinMo phones. I know it's a shocker, but Apple didn't invent the smartphone, they merely re-invented (quasi-created a UI and re-branded it) it.
True, but before iPhone, smartphones are niche products. Anyway, the point is that Apple may not have had choices to pick from.