I think what we need is for some big tech companies to sign a contract with each other that they start dropping IPv4 at their network edge in 2035 or so. This would then signal the market that you're going to need to deploy IPv6 and that you can do IPv6 only, because IPv4 only networks will have to figure out translation in their edges. And I think they should be motivated to do this, to get rid of the requirement of purchasing IPv4 addresses. However they probably will always be able to sink that cost in their products, and the real companies suffering from access to IPv4 spaces are competitors who never start. So it might be a good anti-competitive strategy to keep the IPv4 dream alive.
I'm reasonably sure that those big tech companies are (closely) tracking their numbers, and know pretty accurately how much traffic (direct correlation: revenue) they would lose if they switched to v6 only. Ideally with projections on how much that loss may be in 2030, 2035, ... (with lots of assumptions, sure). What would possibly make them decide to drop 5% or 1% or 0.5% or even 0.1% of their potential customers (and revenue) at that time "for the good of the internet"? Robert