I went down a very similar train of thought, making the same assumption. I think this makes us “type 1” engineers: wrongly assume that we are not allowed to break the existing code contract, and attempt to use it to implement a new solution “over” the old. Extending without modifying.
I took that as a kind of lesson in and of itself. I’ve certainly had to face code monstrosities and cut through multiple layers to discover the simple rewrite before. If somebody had modified instead of extended sooner, if someone assumed the existing solutions were not so sacred, maybe a monstrosity could have been avoided in the first place.
On the flip side I've also experienced the opposite. Someone modifies existing code from an open source library and then we aren't able to safely upgrade it because of tons of merge conflicts with the modifications that were added.
I took that as a kind of lesson in and of itself. I’ve certainly had to face code monstrosities and cut through multiple layers to discover the simple rewrite before. If somebody had modified instead of extended sooner, if someone assumed the existing solutions were not so sacred, maybe a monstrosity could have been avoided in the first place.