So you are estimating based on a coverage map. Ok.
Surely you realize that the coverage map DOES cover all the densest population areas in the US. So the vast majority of people will have 4G coverage. Your 100+ million estimate is likely very wrong. In Colorado, I am unlikely to get 4G if I go camping, but if I am in denver or Colorado Springs or Ft Collins I always have it. If I am along the major highways I always have it. I am guessing it is like that in every state. I know dozens of people with 4G phones and all of them get coverage.
In other words...it is likely that you are the exception, not the rule. Your opinion has to do with your carrier's crappy 4G coverage in your area and/or their dishonest advertising. It has nothing at all to do with your Android phone or Android in general.