This isn't necessarily true. The scarcity of IPv4 addresses could very well induce a lack of demand and decrease the price. You wouldn't dream of developing a technology that requires people to have an individual IP address, so you don't. This massively reduces the demand for v4 addresses. It's not as if there are users out there who will demand the features you can't implement, and it's not as if you could fund the entire IPv6 network by yourself to bring about those features. Then ISPs have no reason to support v6 because no customers demand it. Instead of increased price, the cost is paid through decreased service. Think of a congested road network. It could be well worth it to build some more roads and ease congestion, but if there is no one in the system willing to pay for it, everyone will suffer.