Key word being "widespread".

10GBASE-T dates back to 2006, and we've been seeing it on the odd prosumer workstation / elite gamer motherboard for quite a while now. But those markets aren't going to lead to a full office rewiring.

The entry-level market is more interesting: when will we see it on motherboards that retail for $100? When will we see it on the average Dell Optiplex? When will your ISP router come with 10G ports?

Will some people be using 10G before that? Definitely, and I'll be one of them. Will it be something to consider for the average office environment? Nah.