[jbearamus]

i don't know if we're close to that limit but yes i'd agree that there is a theoretical limit but at the same time, yes there's only so much bandwidth but with each move in generational technology we can fit 5 times as much data in the same amount of space.
now yes there will eventually be a generational limit (just like computer processors evolved to a point then they had to go in a different direction, multicore) I don't think 4G is going to be the end of enhanced technology, it could be 5G/7G/9G who knows but I doubt 4G will be the last.