I believe very few people benefit from even gigabit in their homes. The average user isn't streaming or moving vast quantities of data on the local network; they are surfing the internet and 802.11n is generally faster than the Internet connection.
Historically that might have been true, but more and more 100Mbps Ethernet isn't sufficient. I think you're right that the majority right now might not necessarily need/use 10Gbps, but lots of people do need "faster than 100Mbps" - and 1Gbps is the next step up.
Here, 120Mbps FTTH is being rapidly rolled out in most cities, and on the broadband forums I've found lots of people complaining of their broadband speed being limited by their home (Ethernet) network. Of course it might not be life/mission critical that people get the full bandwidth in their homes, but if they're paying for it, they want it. And considering how quickly we went from 10-120Mbps; I wonder how much longer before broadband gets faster again?
And if you're waiting for an OSX or iOS update, or downloading a new Xcode version etc... every few minutes you spend waiting for a download could mean time you're not getting your work done. File copies across a local network can be very slow too even on 100Mbps Ethernet, and local backups.
I've no doubt that with faster home connections, we'll end up finding some use for it; and it may involve changing how we work - always working off network files instead of local copies etc.?