Gigabit ethernet used to be ungodly expensive. Once 40G or 100G ethernet starts hitting production switches, 10G will start to become economical.
It's been around a long time now, much longer than 1Gb was around until it started becoming consumer products. 10Gb still uses quite a lot of power, and consumer demand is virtually absent since the 10x speed we got from 100Mb to 1Gb has been "fast enough" for home users, and will be for many years.