"But users are already proving reluctant to pay for the additional speed of 3G"
This is because "additional speed" that's only a bit faster, is often pretty sketchy, and has vast swathes of the country with no coverage at all, isnt a particularly attractive service to pay for.
As some of the objections hint at, saying "wow our 3g covers 95% of the population" is all well and good, but that 95% is basically cities., which leaves vast swathes of the country (upto and including fairly sizeable towns, not just ass-end-of-nowhere countryside) with no 3G signal - And guess what? The one place I dont particularly need coverage is 1) the city where I live because i'm at/close to home and 2) the city where I live that has wifi hotspots everywhere anyway.
Superfast mobile net connections are utterly worthless if they cant be used while mobile, which also (funny this) includes outside of cities. Right now, for 3G, that's basically nonexistant. So why is this something networks are suprised people dont fancy paying for?
"Mobile broadband" to be worthwhile and mobile, whether 3G or 4G, needs a requirement of 95% LAND AREA not where-people-live.
Personally, I would fairly happily pay what would probably amount to a small fortune for a 3G or 4G service that actually achieved anything remotely close to the speed advertised and would actually always work everywhere, or at least mostly everywhere, instead of here and there, sometimes.