Blockchain analysis is not a threat to bitcoin decentralization, BTC blockchain is transparent and there is no privacy at the protocol level. So it has always been possible to analyse tx's on the blockchain. I know the tools to do so may have gotten more sophisticated, but it changes nothing, BTC is not a privacy coin, and to achieve privacy there are certain things the user has to do.
I know this doesn’t take away Bitcoin’s potential for many things — it just means real privacy will be harder to keep.
Privacy has always required responsibility and nothing has changed, it is still what is required.