Certain existing lots, structures and uses of lots and structures were lawful before this Ordinance was adopted, but have become nonconforming under the terms of this Ordinance and its amendments. It is the intent of this Ordinance to permit such non-conformities to remain until they are discontinued or removed, but not to encourage their survival or, where discontinuance or removal is not feasible, to gradually upgrade such non-conformities to conforming status. Nonconforming uses or structures shall not be enlarged, expanded, or extended, except as provided herein, and shall not be used as grounds for adding other structures and uses of lots and structures which are prohibited. Nonconforming uses, structures and lots are declared by this Ordinance to be incompatible with the structures and uses permitted in the various districts.