Earlier quoted context omitted.
compared to rolling out IPv6? definitely, especially on the longer term. For instance, most Core/Edge routers (my experience is mainly with juniper MX series, but i assume the model is roughly the same for other vendors), you need specific licenses or interface card's to do stateful services like NAT. Compared to doing IPv6, which is "just forwarding packets" and doesn't require the hardware to track state in nearly…
You’re presenting a false dichotomy. The choice for an ISP today is not “v4 or v6”, it’s either “v4 or v4+v6”. A v6 only connection in the US is unusable.
And v6 connections help drop the pressure on NAT resources - and sites that are optimizing for mobile connections are already going to be on IPv6 where possible (due to mobile networks prioritizing v6 traffic for various reasons, including licensing - and NAT resource costs)