>decentralize
Bitcoin has central banks you just call them exchanges and wallet providers. Most cryptocurrencies depend on specific websites and central developer teams(who may decided to fork the currency blockchain at their whim).
Of course Ethereum is one chain that infamously forked. That was only possible because all the client devs agreed to do it, and most users chose to use the new software. (Some didn't, so the original chain still exists as ETC.)
Bitcoin would continue to exist without the exchanges and wallets, they are peripheral to the core technology. Blockchains can't be 'forked at a whim' without majority consensus, that's the whole point. ETH is the obvious example where the devs forked with support from the community and it led to the ETH/ETC divide.
You could ask what would happen if Cisco tried to force a new version of TCP/IP with unwelcome changes?
The comparison isn't quite the same yet, but it could be in the future and many bitcoin supporters think that's how it will turn out.