He's wrong. Not only do we have a lot of space in 2000::/3, but we also have five completely untouched /3s available, so if we do somehow run out of space in 20

He's wrong. Not only do we have a lot of space in 2000::/3, but we also have five completely untouched /3s available, so if we do somehow run out of space in 2000::/3 we can always start using one of those /3s with tighter allocation policies. Plus, the idea of waiting until we "run out of v4 with NATs" is getting it wrong. NAT starts causing problems long, long before it gets to the stage where the very last person says "I give up".