Re: unlimited anything is a guaranteed fail...
The difference is that there is no finite reservoir of bits that's about to run out if everyone uses them up. This isn't like dragging a few kilowatts out of the mains grid and expecting the power station to stay fuelled forever.
The problem is, too many people seem to think that there is some kind of bit reservoir. There isn't. The only limit is the amount of data that can be transferred in any given time period. With sensible traffic management and by not oversubscribing your networks with endpoint connections that are way too high for the core network to cope with, then yes, unlimited usage of a mobile network connection is very possible. Three are managing it right now.
2mbit is a bit low, though.