You’re risking your life and the lives of others. You must remember that driving a power steering car without a functioning pump is not driving a car with manual steering, you’re having to work against the hydraulics in the power steering system.
There’s also a liability issue involved. If you were to get into an accident, and it was discovered that it resulted in your negligence to keep your car in working order, there’s a good chance you’ll get taken to the cleaners, I wouldn’t count on insurance covering it either.