You can’t really go to the cellular network for broadband. They are having issues keeping up with demand. ATT recently jacked up their data plan from 25 for 2gigs to 30 for 3gigs. You go over that, you spend another 30 bucks. Streaming videos to watch instead of cable will not be practical like that. Every carrier except Tmobile that I am aware of, have got rid of their unlimited data plans.
Cell phone companies on the whole are experiencing rapid growth in data usage due to the smart phones. They will rapidly hit the wall where there is no more spectrum to buy.
I think they will get it figured out before a wall is hit. They are always figuring out ways to cram more data onto a carrier wave. They are even working on eliminating carrier waves completely...as in ultra wide band radio transmission. If we have to switch to sat phone/cell phone hybrids that operate in the microwave spectrum, so be it. Or if we have to switch to cell systems that use more towers spaced closer together, so be it.