The point is not “raising the vehicle height would be cheap”; it obviously wouldn’t. The point is that one of the key requirements was maintaining the 737 type

The point is not “raising the vehicle height would be cheap”; it obviously wouldn’t. The point is that one of the key requirements was maintaining the 737 type certification. If that requirement was thrown out, they would’ve made a better airplane that wouldn’t have sold anywhere near as well as the MAX8.