Major residential ISPs aren't rolling out IPv6 largely because they already have enough IPv4 space for their customers.
Take a major UK ISP like Virgin Media. According to Hurricane Electrics BGP looking glass project they are originating 9.4M IPv4 addresses[0], however, at the end of 2012, according to Wikipedia[1], they only had 4.8M customers.
Virgin Media can't even expand that easily because they must lay cable in areas that weren't covered by NTL/Telewest infrastructure: and I believe is extremely expensive and time consuming with planning permission being what it is.
Take a major UK ISP like Virgin Media. According to Hurricane Electrics BGP looking glass project they are originating 9.4M IPv4 addresses[0], however, at the end of 2012, according to Wikipedia[1], they only had 4.8M customers.
[0] http://bgp.he.net/AS5089#_asinfo [1] https://en.wikipedia.org/wiki/Virgin_Media