Is it true that a cheaper TV that has been correctively calibrated can look better than an expensive television that has not been calibrated?

Yes, if we’re comparing apples-to-apples in technology. For example, an entry-level LCD TV with limited High Dynamic Range capability and no “local dimming” feature will look superior once calibrated and compared to a more expensive entry-level TV with the same feature set. The same can be said of a correctively calibrated high-end TV; it will always look superior to one that is not. It would be unreasonable to expect an entry-level TV to exceed the performance of a television designed with high-intensity LEDs and multiple local dimming zones for greater brightness and black level capability.