Yeah. It is a trivial assumption. In my experience with Comcast Residential internet, one's IPv6 prefix remains the same for as long as one's IPv4 address, which is to say that they remain the same forever.
Comcast hands out allocations as wide as /60, but even this doesn't help much with privacy; if you're being unusually proactive with your network renumbering, that's only four bits of entropy that you're adding to your identifiers. :)
Comcast hands out allocations as wide as /60, but even this doesn't help much with privacy; if you're being unusually proactive with your network renumbering, that's only four bits of entropy that you're adding to your identifiers. :)