[ReK_]

Except it's not 16 million containers. You need addressing for every link in the network. Want 10 racks of 20 servers with redundant switching in each, redundant spines in the network rack? That's 60 physical links, each of which need two addresses, and that's just the fabric underlay network. You haven't created the actual overlay networks yet, which you need multiple of (front end, back end, database, storage...).

Consider that 200 servers is a drop in the bucket at some scales, you can see why data centre is moving to V6 only.