That article (from the URL) appears to be about Bitcoin, not "crypto"
And the distribution of Bitcoin might be skewed because one of the largest holders (Satoshi) is possibly dead, and many others would be custodial addresses (centralized exchange addresses, and large funds like microstrategy).
Furthermore, many of the addresses being considered would be inactive addresses by people who have moved on to new addresses. In that case, you have many addreses with "dust" balances which are not claimed by anyone, perhaps as much of 80% of addresses which have ever been used. I have gone through at least 6 such addresses myself, and I no longer use the Bitcoin network (or have funds on it)
It's a lot different than the dataset used for considering wealth distribution among a known population number, whose monetary declarations are necessarily exposed to a government which can publicize this kind of data in a more accurate way.