The rather strange desire to avoid switching to IPv6 has even lead to reports that some Internet Service Providers are enacting Network Address Translation (NAT) at their data centres. In other words, their customers at homes and businesses are being given addresses that are routable only on the ISP's network, and not on the wider Internet.
To simply even further, this means that while such customers will be able to browse the Web and grab e-mail just like everybody else, they'll be unable to use file sharing services, or some services such as video conferencing--effectively, they'll be denied any service that involves one computer directly talking to another across the Internet.
It's a little like being only half a person on the Internet. Some commentators have suggested that it turns a user into nothing more than a content consumer, who can be fed data by their ISPs, but who doesn't have the freedom to go out and fetch what they want, or experience new services that require a genuine, routable IP address.
Of course, not all IPv4 addresses that have been assigned are in use. In fact, the ratio of assigned to in-use addresses is probably lower than many might think. I suspect many organizations are holding onto IP addresses they've been assigned by their ISP or RIR, but have no intention of using. It simply makes business sense to do so in order to prepare for possible future developments. This has certainly been the case at businesses I've worked at in the past.
Some kind of amnesty whereby organizations surrender unused addresses is a possibility, but it's extremely unlikely to become a reality. If nothing else, the biggest question would be who would organize and administer such a scheme, and what financial benefits they would receive (and who would pay).
Any measures such as this can only be temporary because, as must be obvious, IPv6 is coming whether we like it or not. It's simply the most sensible and correct solution. If you haven't already, get in touch with your Internet Service Provider and ask when they're planning a switch to IPv6, and what the implications will be for you. Will you need a new service contract, for example? New hardware?
Additionally, it might be wise to start experimenting with IPv6 addressing within your organization; there are many books and guides out there explaining how, and it's surprisingly easy to do.