I won't address the IPv6 landmine here, because that is its own can of worms, and there are plenty of real, legitimate criticisms for not adopting it.

That aside, while I do agree that small private IPv4 space availability is a real concern, I'd also argue that Docker choosing to make the default network size a /16 compounds this problem significantly. I've never had a workflow where a Docker network needed more than a /24, and most could get away with a /26 or /27 without it being considered an aggressive limitation of IP space. Assigning the default Docker network size to something much more reasonable for a development context would do wonders for limiting collisions like this in the first place.