Bitcoin has not lost it's centralization--it's the only truly "decentralized" digital currency in the sense that a central entity could not easily take control of it (although it's not completely impossible, just very hard and very unlikely to happen).
All other cryptocurrencies are "centralized" in the sense that they can be, relatively easily, controlled by a single entity e.g. a government that wished to order it to do something. (This is due to them being a PoS model, or simply a smaller network that could more easily be taken over with a 51% attack).
Bitcoin's market cap today is about $1.1T. The
total market cap of digital currencies is a little over $2T.
In other words, almost half of today's market, as defined by individual investors voting with their money, is not decentralized.And on top of that, most individual holders of Bitcoin hold it using a broker or an app--a
centralized entity that holds their Bitcoin keys (or more often, simply a database entry connoting their holding), meaning that most consumers don't use Bitcoin in a centralized way.
So Bitcoin hasn't lost it's decentralization, the
broader market for digital currencies has. Consumers have shown us that they
do not care about decentralization--all they seem to want is a
meme investment instrument, not a hedge against government intervention or all of the stuff Bitcoin was founded to do.
Satoshi invented a system that was very useful and interesting to... thousands of people across the world. Then millions more people started using that same invention for something he never intended: speculation.
(And can somebody explain why you should use the blockchain architecture for a system that is effectively controlled by a single entity? That sounds completely pointless to me).