Yes and no. Imagine some super intelligence tackling the unmaintainable mess. It can untangle it, but the problem is that unless you have a test suite that's covering 100% of possible cases (which should on it's own enough to build the codebase), you will stumble upon "what's actually the intent here" problem. Some other software depending on buggy behavior on this one etc.

Which is why I think additional intent preserving abstraction is where software coding agents are likely heading.