Well, your anecdotal data doesn't line up with the facts. There's a Verge article from a month ago[0] that contains LTE coverage information for Verizon, AT&T, and Sprint. There's simply no comparison - Verizon is leaps and bounds ahead of AT&T. Just because you have AT&T LTE in your neck of the woods doesn't mean that the vast majority of Americans do.
The valid metric to observe in asserting AT&T's LTE coverage's uselessness is not relative standing. We should measure the number of people who can be reasonably expected to have LTE coverage a reasonable percent of the time.
That's a pretty useless chart. It appears to be just charting carrier claims.
I'm not saying you're wrong, but yeah, the chart is flawed. Dallas, TX shows Sprint for example, but Sprint's LTE in Dallas is notoriously bad. As in, many people never see it, and I've never seen one single person claim to get it regularly. I think I've seen it mentioned that the maps are "4 to 5 year" projections, but today's actual coverage is something like 4% of DFW.
0: http://www.theverge.com/2012/9/21/3367602/iphone-5-lte-marke...