The problem in the US is that the major carriers pretty much do thing their own way and refuse to use the same technology and frequencies. Good old American competition without much regulation has pretty much ensured our cell phone market is a disaster compared to the rest of the world. A similar setup also explains why the US is so far behind in broadband.
Lets see, in pretty much any country in Europe, you can bring a phone onto any carrier, so the carriers are much more focused on providing good coverage and competitive rates to stay ahead. They sign agreements with each other to allow roaming when needed, to ensure even slight weak spots in their network are covered by the other guys.
In the US, you have 4 towers sitting in the near same spot, and no phone can use all four towers. All the carriers pretty much charge the same monthly rates, do nothing to discount your plan if you bring your own phone, and rarely sign roaming agreements.
Ultimately the US need just enough regulation to foster true competition. Make sure the providers are competing for customers, instead of colluding and doing the minimum amount of work necessary to rip off the public. Things may get better once the providers all move to LTE, but only time will tell.
Oh, and on the topic of the iPhone 4 specifically, I did return mine over the antenna issue. Here in Austin, it was definitely an issue, but wasn't a problem in Portland or Seattle. While I wasn't dropping calls, touching the spot did result in the other side usually not hearing me. Though I don't normally use the phone function much, this did come up as an issue when a 911 call was made. My friend in the car used an iPhone 4 to report a very intoxicated driver who had nearly collided with my car, and was generally making a mess of highway safety. It took 30 seconds for me to finally remind my friend he was probably touching the spot, all while trying to deal with an emergency situation. I've never used a case on any of my iPhones, and while I appreciate the gesture to give out free ones, it doesn't make me satisfied. So I did the one thing I could and returned the device to await a proper fix, one that doesn't require me to find new accessories that work with an iPhone in a case. For those satisfied with the phone, enjoy it. It was a great device outside the antenna problem.