I would love to see a more recent source if you have one.

Regardless, possession of IP addresses doesn't change all that much. In the early days a company could buy an entire Class A (1.X.X.X) address space comprising 16million+ addresses for their private use. There are still many companies holding large blocks of addresses, and most of those companies are in the US, and they don't just give up those addresses.

The point being, there's significant resistance to redistributing addresses once they've been allocated. They don't change hands terribly often (and keep in mind we're talking about actual internet addresses, not local network addresses that are being dynamically assigned and NATed across router domains).

Of course English is spoken in other countries, and other countries have high numbers of internet users, but it does not follow that English is a commonly used language for internet users in other countries. Most Chinese are probably speaking Chinese, most Indians are probably speaking Hindi.

The IPv6 graph you linked shows that adoption is still less than 50%, and I'm not clear on their methodology... does "users that access Google" mean users with Google accounts? or individual users that use google.com? or does it include all of their cloud services? do web servers linking content from Google Ads count? does this data represent mostly end users, or also infrastructure connections?

These graphs do not give an indication of how many users per country there are. There are in fact statistics on that which expectedly show China and India on top.

Well sure, but people from those countries are far less likely to be speaking English, which is why I said:

It is entirely rational to assume that an English-speaking person on the Internet is from the US, given no other information.

The prevalence of internet use in countries with primary languages other than English has no bearing on this statement.

The point of using the IP address statistics is to show that the vast majority of websites on the Internet were created in the US for the US market, and that is still true today.

On a side note, the distribution of addresses is unbalanced but it isn't "bad". It is a consequence of a system growing over time. Communications infrastructure cannot pop into existence everywhere all at once, and realistically not many people outside the US had any interest in the internet in 1983.