The main problem is that there is no legal definition of "4G". If it is 1% faster than 3G they can call it 4G and I'm not sure there is much you can hang them for. Its completely misleading on their part... "Faux G" I think is how sprint described it.
They probably have a massive team of lawyers that signed off on it before they did it. That doesn't mean they can't be sued.
I did find
this online, may be of interest.
I believe you're right. I don't think a lawsuit will go very far. If AT&T is guilty of false advertising with it's label of 4G, then they all are. None of the carriers have a true 4G system as it's defined by the ITU. Some use 4G-era technologies like LTE and WiMax. But are not true 4G by definition.
The problem AT&T committed, that none of the other carriers have done, is roll out two 4G technolgies so close together where the hardware will not work on both networks. Since it was so close, they should have put LTE chips in all their 4G products. I had a phone with a WiMax chip in it over a year before I finally got service. This would have been much smarter.
In comparison, if you bought a Verizon 4G device, you are good to go for years. Same for T-Mobile
(unless the AT&T buyout goes through). Even the TIer 2 Carriers are getting the transition right. Sprint is a different deal, though. They kind of are committing the same atrocity since now they are starting up an LTE network with LightSquared next year. But at least there was a few years in between. Many folks will be out of contract when the LTE begins.
What AT&T needs to do to mitigate this problem is to complete a full buildout of HSPA+ and fast. They also need to allow an upgrade to all HSPA+ device owners at contract price, without extending the contract. Although you would have to shell out another $200-$300 for a new LTE device, with these terms it would be pretty fair.
Sprint also needs to consider something like this with their WiMax customers. In fact, Sprint is more likely to stop building out WiMax than AT&T stop building out HSPA+.
But I imagine neither carrier is going to do anything like this. That would be good customer service! And that'll never happen.