Earth has about 2^170 atoms. If we ignore the core and mantle, focusing on the crust, surface and atmosphere, we should be able to cram it into IPv6. Even if we add a couple planets and moons in the future. At least if we stop giving each person 18 quintillion IPs just because we once thought encoding MAC addresses in the lower 64 bits was a good idea.
Addressing isn't really the big issue with IPv6. The main issue is that moving to mobile networks means all its assumptions about how routing will work are wrong, since you don't want to lose IP connections when you move across cell towers.