So curious, what is wrong with just letting people switch over as they need to? What does it matter if the switch is sped up by a few years? Some are happy with their current ipv4 addresses, and then maybe if they need to buy new ones only ipv6 will be available at which point they can decide for themselves to switch over. As long as browsers and DNS services can work with both, it shouldn't matter, right?

Here I'm assuming that infra teams already have a lot to do and would experience some harm having the government give them more user stories. Maybe not tons of harm, but what is the other side of the equation that justifies the harm?