As he explains you don't need an ipv4 address for every person. Just give em a shared one and use NAT. Our entire office has just one public IP address and nobody knows the difference.
So when your entire neighborhood is NAT'd and you want to use XBox Live you'll, what, call up your ISP and ask nicely to have the right ports forwarded to you?
NAT works in an office environment because most offices aren't doing anything more than web and email. Home usage scenarios are significantly broader and harder to keep working behind carrier grade NAT.
Presumably (I haven't got one) the XBoxes can use UPnP to negotiate external ports with the home router, which, unlike the ISP's router, can trust the devices on its network.
For every techno geek like us, there are many more people with 0 devices that require an IP. OP was comparing number of IPs in IPv4 with number of people on earth. Since we are only just now starting to run out of IPv4 addresses (the last big blocks were assigned recently, but there are still gaps and sparsely filled blocks), it seems safe to say that on average the number of IP enabled devices is lower than the number of people. That won't last long though.
As technology filters down to the third world, and (assuming there isn't some massive device convergence that reduces demand for IPs in the first world) the ratio of devices to people will rapidly become skewed. It's a lot easier to pump out cell-phones than babies after all :D
Totally workable solution, but i have to point back at djb's argument.
If there is even a single customer that only has access to ipv6, you have to support them 4 and 6. My office, and your office will of course stay on ipv4. I'm pretty confident least one university will soon be strapped for cash, and sell of the boatload of their ipv4 space, and just give the dorms ipv6 addresses. there will be much whining and complaining, and everyone will support ipv6 the next week.
