Depends what you're looking at, on mobile it absolutely is. Not sure what the situation around the world is but in the US pretty much all LTE connectivity is via v6. T-Mobile at least doesn't even dual stack, if you need to go somewhere that's v4 only they do NAT64

It's hit 35%, and has broken 40% in many countries: https://www.google.com/intl/en/ipv6/statistics.html

IPv4 will probably never go away because it's a better choice for private networks.