I think an understated thing that's been happening is that people have been investing heavily into their desktop workspace. Even non-gamers have decked out mics, keyboards, monitors, the whole thing. It's easy to forget because one of the most commonly accepted sayings for awhile now has been "everyone's got a computer in their pocket". They have nice setups at home too.

When you have a nice mic or headset and multiple monitors and your own private space, it's totally the next step to just begin working with the computer with voice. Voice has not been a staple feature of people's workflow, but I think all that is about to change (Voice as an interface, not as a communication tool, that's been around since 1876.