Relatedly: wouldn't there be many applications for which ipv4 isn't needed?

For example, Walmart has electronic eink shelf tags they can update remotely. Each one needs a unique address. I wouldn't think it needs ipv4. It doesn't have to connect to the SpaceJam website.

I would think that as time goes by, the number of these new devices would swamp the number of old ones that need ipv4. v4 would still be around and might even seem important to the fogies using web browsers on laptops...meanwhile the street lamp has five ipv6 addresses and no ipv4 ones.