It comes down to there being logical use case scenarios for it.
Most computers can't write to disk at 1Gbit/s, and the power and related infrastructure (multiple PCIe lines) required for a 10Gbit Ethernet transceiver is higher than for a gigabit one.
When some application comes along that is greatly improved by 10 gigabit networking (rather than point to point like Thunderbolt, USB3, or SATA), then we'll see it happen.
It's hard to predict; 10G prices have plateaued or increased in recent years, so maybe the answer is never or maybe there will be a dramatic price drop some day.
That is not an ethernet device. Consumer devices have had non-ethernet interconnects faster than 1 Gbps for a while now. (eSATA, USB 3.0, lots of internal interconnects such as PCIe.)
