ATT *hopes* we think HSPA+, etc will fix the problem. It won't. The problem isn't a carrier signal. It's spectrum, backhaul, and plain oversubscription.
ATT sold massive amounts of unlimited data plans, data handsets, and didn't have the spectrum from the handset to the tower to do it, regardless of what 3G technology or 3G+ technology they try to schelp.
Then, they simply didn't do the investment (or couldn't get approval) for the right physical presence sites to operate the various spectrum they bought at auction/from the Cingular acquisition. They had their old TDMA stations they migrated to GSM and later to 3G, but the physical design of a voice-centric TDMA network (e.g. the spacing/needs/density of physical sites) is MARKEDLY different from a GSM network, let alone a network evolving into being very data (packet) centric.
Then, from what under-built physical network they did deploy, they didn't build in a very good backhaul infrastructure.
ATT isn't stupid, neither is it poor. But, they do have some massive leadership issues, some difficult legacy/technology/real estate/heritage/acquisition issues, etc that are all exacerbated more on the focus more on marketing & sounding good than walking the walk.
This HSPA+ thing is a great example. de Vega and team are putting Fancy Feast on a plate and calling it fine Foie Gras. They want to win this "4G" war in words & labels when they really should be focused on winning the "customer experience" war. They're *lying* (and they know it, how can de Vega go up there and call HSPA+ 4G? He's got no ethics). HSPA+ is NOT 4G. It's sexed up 3G.
It's not a question of whether they can do it, the technology exists, or even if the capital exists - it's a question of willingness, culture, and priorities. ATT shows what theirs are everyday, and it's not the build out of a network with the best customer service. That company is called Verizon

(they have their own bevy of issues, but being focused on network build-out and coverage is NOT one of them!).