The answer is that the carriers are busy adding capacity for our insatiable hunger for data instead of helping us sound less like C3PO. Voice calls are not the growth segment of their market. A recent CNN article noted that good-sounding wireless calls are available, on "HD" phones, but not in the US. Count Canada, the UK and Uganda, yes, Uganda, among the 22 countries where more normal-sounding phones are available. Not here.
There's hope. Higher-quality phones require more bandwidth and there's more bandwidth to be had on the new LTE networks. You just need an "app" for that. This is assuming we will still be talking to each other. TTYL?