The reasons that people 20 years from now will have problems remembering how they got by with under 80mbps either haven't been invented yet or have been the province of a very small minority of people. Back when I owned a 2400baud modem, upgrading to 14.4kbps struck me as ludicrous; only a couple of local BBSes supported it and what the heck was I going to be transferring at those rates, anyway?
One immediate application that springs to mind is making server-stored content nearly as accessible as what's locally-stored. IIRC a typical cheapo 7200rpm HDD will transfer data at just about that speed. "Cloud computing" and such makes much more sense to me at 1gbps than at 6mbps.