Completely false and incorrect assumption.
What is the validator incentive structure for validators not run by Ripple?
If the XRP Ledger becomes successful and is widely used for interbank settlement, there will be an incentive for participants to ensure the reliability and stability of the network. If this happens, institutions will run rippledservers to participate in the network. Once you are running a server, the additional cost and effort to operate a validator is essentially zero—it would simply involve flipping a software switch from off to on. It is the validators who decide the evolution of the XRP Ledger, so the primary incentive to run a validator is to preserve and protect the stable operation and sensible evolution of the network.