Ran across a comment a while ago on some fun "IPv6 math":

    On the surface of the Earth [land+water], there are 8.4 IPv4 addresses per km². Not counting the oceans, that would be 28 IPv4 addresses per km² land.

    IPv6 gives 10¹⁷ addresses per mm² (yes, square millimetre).

    In terms of volume, 10⁸ IPv6 addresses per mm³ throughout the Earth.

A second way of thinking about it:

* Stars in the Milky Way: 400 Billion

* Galaxies in the universe: 2 Trillion

* So (4x10¹¹)x(2x10¹²) = 8x10²³ stars in the universe.

* Size of IPv6 address space: 3.4x10³⁸

* Find the ratio between addresses and stars: 3.4x10³⁸ / 8x10²³

IPv6 offers about 430 trillion times more addresses than estimated stars in the universe. From Tom Coffee's presentation "An Enterprise IPv6 Address Planning Case-Study":

* https://www.youtube.com/watch?v=7Tnh4upTOC4

But it is really about more than just the available pool of addresses.

Much of the IPv6 rollout challenges have been centered around routing and security. It's great that I can personally have (in theory) more IP addresses than I would ever practically need (and I am saying this as someone with 200 IP endpoints just in my house), but if I can't easily manage and control access much of the theoretical benefit goes away.

IMO, IPv6 solved the address pool size part of the issue, but it made managing the v4 to v6 transition very painful.