Maybe I just suck at reading, but I'm not sure I get the argument for why function overloading and constructors are required for RAII. Is it some interaction with C and C++'s object models that I clearly didn't understand?
There are 2 ways to get C++-style RAII into C. The first way is to wholesale import the C++ object system into C (which means name mangling, all the different flavors of constructors, destructors, etc). Conceptually this would work, but it's never going to happen, because implementing that would be literally more work than an entire conforming C99 compiler.
The second way is to just use some special function attributes to signify that a function runs when an object is created on the stack / popped off the stack. This won't work either because the C++ object system also solves lots of other problems that this simpler system just ignores (such as, what happens when you copy an object that has a constructor function).
When I started reading it, the first thing that came to my mind was the issue with copying the structs. The article started looking at the issue, but didn't really follow further with the changes needed to make it work, which is that you start needing to introduce tracking which instance is responsible for the resources and providing a way to transfer that responsibility (a.k.a. ownership and move semantics).
amateur C++ coder