New LIRs - holders of /22 - have all the incentives to deploy IPv6
already (because they do not have enough IPv4 to number everything with
public v4 addresses) - but how would such a policy incentivize a big
content provider that has enough v4, is not growing in number of external
visible services (= doesn't need more v4 addresses), and has no v6?

These are the sore spots today: content and cloud providers - and neither
are likely to fall under this policy.