You're technically right - but you're describing something that's kinda like the opposite of scope creep.
I can 1000% buy that the system was designed with only texture swapping in mind as that's typically how game dev would go - the idea to expand it to cover other systems currently in the game probably never got thrown out there during the planning phase resulting in a system that is limited to textures only.
Now, the system can ofc be expanded to model swapping 1000%, but the issue now is that you have to refactor a system that works well and does its job JUST to do a feature that doesn't actually bring you any kind of direct benefit.
Essentially it's tech debt - to be fixed later.
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