No no no no and no....
You don't have to dump any - just choose square format as you would with medium format.
If you want rectangular, you can have it. And sensors are getting cheaper, so wasting part of the image isn't that, er, wasteful.
At the moment we're paying £££ for lenses and wasting much of the image by having a 1:1.5 format. A square sensor would make maximum use of what the lens sees.
You know it makes sensor.