That is because proving that it isn't is a major task that involves dissecting the codebase, its current specs and planned future features (a seemingly pointles

That is because proving that it isn't is a major task that involves dissecting the codebase, its current specs and planned future features (a seemingly pointless abstraction now can be the groundwork for a new module that will appear soon[0]). Thus the asymmetry between adding and removing abstractions. [0] where soon either means really soon because product management needs it yesterday or never because there is too much work to do in other places.