Your statement is true but given propulsion pods have been around since introduced in the 1980’s I doubt if things will revert to shafted propellers. The propulsion pods have just too many advantages. They eliminate the need for separate steering gear, and stern thrusters. They require less space. They tend to generate less onboard noise. Being electric, they integrate easily with diesel electric plants. Reliability has improved since they were first introduced and will likely continue to do so. The pluses far out weigh the teething pains of development.
One of the problems is that cruise ships continue to get larger putting more, and more strain on said equipment.