IPv4 isn’t depreciated, it’s exhausted. It’s still a key cornerstone of our current internet today.
We still have “modern” hardware being deployed with piss-poor IPv6 support (if any at all). Until that gets fixed, adoption rates will continue to be low. Adding warnings will only result in annoying people, not driving for improvement.
Now I’m wondering what the minimum amount of water required to sustain the current levels of life on earth.