AT&T knows that, which is why it is planning its first LTE deployments later this year. T-Mobile is likely to be absorbed into AT&T, so its customers will get LTE that way. If the feds somehow grow a spine and block that acquisition, current owner Deutsche Telekom has been starving T-Mobile for years of capital infrastructure funds, so T-Mobile is likely to ride its faux 4G for the foreseeable future.
LTE is deployed today in parts of some cities by Verizon Wireless and Metro PCS. Sprint too recently adopted LTE by partnering with a new infrastructure provider named LightSquared that gained notoriety for a proposed deployment approach that could have scrambled GPS signals (unsurprisingly, that proposal has since been adjusted). LTE is also forward-compatible with LTE-Advanced, the 4G versions likely to come next in the United States; any LTE devices in use when LTE-Advanced makes its debut should continue to function on it.
Sprint is also a partner in Clearwire, a company that has deployed WiMax networks in several dozen U.S. cities. However, that partnership is on the rocks, and Clearwire is now belatedly looking to joing the LTE club. WiMax is more like Wi-Fi than LTE in its underlying technology approach, which means it requires unique radios in devices that use it. Thus, very few smartphones or mobile hotspots can use WiMax. This means WiMax is essentially a dead end for those yearning for 4G's promised faster speeds.
LTE is clearly the only route to 4G, but it's not a single road
It should be obvious that, carrier marketing aside, LTE technology will be the first real move to 4G networks.
Already, several Android smartphones come with LTE radios in addition to 3G radios; if you live in an area with LTE and prefer Android, you can be one of the first to ride the faster 4G wave. Available now are various LTE-enabled Android smartphones from HTC, Motorola, and Samsung, plus an LTE version of the Samsung Galaxy Tab 10.1. Expected next month is the LTE-enabled Motorola Mobility Xoom tablet. A BlackBerry Curve model is also widely expected to be available in an LTE edition next month, and RIM may also ship its promised LTE-based BlackBerry PlayBook tablet by the Christmas holidays.
Apple has been mum on its LTE plans from the iPhone. Although some rumors say the expected iPhone upgrade coming this fall will sport an LTE radio in addition to 3G, I suspect it'll be 2012 before Apple enters the LTE arena, once the radio parts are more proven and the LTE networks are more widely deployed.