It would be really bad for business if Comcast started assigning static addresses for all their customers. The doxxing villains would surely take advantage of

It would be really bad for business if Comcast started assigning static addresses for all their customers. The doxxing villains would surely take advantage of a world in which same address == same person. If some dodgy site gets a visitor from a Comcast netblock they would know that, should they ever de-anonymise the address, the John at the other end has zero plausible deniability to fall back on. That being said, there’s no excuse for Comcast to at least give you the option of a static /48. I see that they themselves have a /20. That alone is enough for a /48 for each of 268 million customers (8x their current userbase) who would each be able to route 65k broadcast domains (/64 subjects.)