It's still 16% of the coins mined so far , not 23% of all coins that will be mined like in case of zeta.
And what you're saying about bitcoin are assumptions , while in this case we have proofs.
We still have no proof it is an individual or an exchange wallet either way. Anyway I don't like the idea of someone owning 23% either, but I don't like the idea of 1000 people owning half of the Bitcoins as well. Bitcoin is no more fairly distributed than the traditional wealth and finance world which goes directly against what Satoshi intended. And while more coins can be mined in the future, who has the money anymore to mine and accumulate a significant chunk of Bitcoins but big multi-million dollar mining farms? Bitcoin is not decentralized like people think.
Why set up multi million dollar farms when you can buy 10k coins with 4 millions?