Basically, this is what is going to happen:
Some ISP somewhere with a /20 is going to project that in 6 months time they will be out of IPs,
and it's going to be too expensive to buy another /20.
So they are going to buy some Cisco-hardware-NAT-appliance and say to their customers: "look here,
you are all on NAT from now on, if you want a real IP you pay extra."
This NAT box will NAT a /20 to a /24 of temp addresses+ports. It will be plug-n-play and
easier than setting up IPv6.
99.9% of customers won't read the announcement and won't notice. They are all NATing through
their DSL modems anyway, and this Cisco equipment will have hacks for all those special
apps that need it to work behind double NATing.
And no one will ever think of switching to IPv6
-paul