I'm sure that the system can work in this "dumbed-down" state, because there may be times that some of the cameras are obscured (rain, snow, malfunction, etc.) so it's probably designed to work in that way. However, I do agree that using less cameras would also reduce safety, so I can't see Tesla doing that.
However, I can see Tesla removing some convenience options (like automatic lane changes and all features that are tied to navigation like the highway-to-highway transfers).
Another thing to consider is that maybe Tesla is bound to FTC requirements. I remember years ago Apple needing to charge for features already in the phone due to FTC reporting requirements. Depending on Tesla reports things, they may not have a choice? Maybe someone with more financial experience could chime in.