[cbhl]

I suspect the big reason it hasn't happened yet is it would require ISPs to replace tens of thousands of dollars of hardware and it would increase support requests in the short term ("site XYZ is broken but it's fixed when I turn of IPv6").

[derefr]

That, and—unlike TLS—there isn't any class of business-destroying vulnerability whose easy solution is IPv6.

[swift]

Is the hardware you're talking about the network equipment controlled by the ISP, or the routers and modems in customers' homes? I'd be surprised if the former hadn't been IPv6-ready for many years now, but I can imagine many customers are still using ancient hardware left over from when they first signed up for service.

[tsomctl]

If you have cable, a number of providers have been making customers upgrade to the newest modem. A single old modem that doesn't support docsis 3 will slow down everyone in your neighborhood.

[curiousGambler]

Really? Interesting... can you elaborate/provide some reading?

I'm a software engineer with a smidge of basic networking experience so not completely clueless, but definitely inexperienced with DOCSIS and this sort of residential networking stuff.

[lima]

ISPs love IPv6 because they lack IPv4 addresses.

Here in Germany, you no longer get IPv4 addresses from Unitymedia.

[djsumdog]

How to people get to IPv4 sites? Do they setup a transparent tunnel of some kind?

[lima]

Yes, they use something called DS-Lite were IPv4 gets CGNATed (many customers share one IPv4).