I am that someone else because I seldom edit the makefiles and I forget things. That's why I try to trim unused targets and recipes and I try to keep it documented.

In the end it is no different from any code that's suffered from 10 years of tuning and it can get ugly. Maybe Make is even somewhat worse in this respect, but then again it does not need to be changed often.

I would let the expert do his job and I do mine.