http://fortune.com/2017/10/16/ibm-blockchain-stellar/
According to Lund, though, the banks use of Stellars digital currency is likely to be temporary. He predicts that, in the next year, central banks will begin issuing digital currencies of their own, and that these will become an integral part of blockchain-based money transfers.
But what is going to happen when people realize that a centralized bank's "blockchain" is just a regular database...
Exactly. As any other database it can be replaced by another without consequences for the top layer of the system. The day will come when IBM replaces Stellar for "IBM-Stellar" and keep the rest of the infrastructure in place. Nothing to stop them doing so.