Re: IPv6 isn't happening any time soon
Hmm, I think Facebook already uses both IPv6 and IPv4, so do many if not all Google services. You'd be surprised to see how many services are already available via IPv6.
You also seem to misunderstand that it's not a "migration". Just like companies who got e-mail didn't turn off their fax machines. Of companies that got fax machines didn't stop receiving letters. People will keep their old IPv4 connections, just like mobile phone users still keep SMS and GSM telephony around.
However it's so much easier to start new services via IPv6. For example building a decentralized network is a pain on IPv4, however it makes sense if you want to do things like social networks. With IPv6 this can be done trivially.
Recovering old IPv4 ranges might save you a few months, but that would actually be a migration effort. You'd need to change the IP-adresses which is a _lot_ of work.