What I learned about IPv4 at the turn of the century allows me to comfortably plan and manage networks up to a few thousand nodes, maybe a few tens of thousands.

I don't work in networking anymore. I really don't care about what those who are in that business. What you need to manage contemporary billion-node size networks and interchange between them is not my problem. You try to make it my problem, but I don't care.

I'll continue organizing the very few and very small networks that are still my responsibility using pre-CIDR ideas.

Maybe it becomes impossible some day. I'll deal with it then.