said by AnonMe :
Given the lack of CPE support, does that roughly 3% of Comcast's customers have their computers plugged directly into their cable modems with no router or device in between?
There is not a lack of CPE support. Almost every router from the major brands has v6 support out of the box now and most of the routers sold over the last 2-3 years has newer firmware with v6 support. ISPs will be rolling out firmware upgrades for their own provided CPE as Comcat has/will be doing.