AI is already better at understanding code than 99.99% of human, the more I use it the more I believe this is true. It can draw connections between dots far quicker and accurate than a human could ever be.
At very least, AI is going to be a must even as a co-supervisor to your project
What in doubt right now, is whether AI can manage a codebase fully autonomously without bring it down, which I doubt it can at the moment. Be it 4.6 or 5.4, they always, almost always, add code instead of removing them, the sheer complexity will explode at certain point.
But that is my assessment for models TODAY, who knows where they will end up being in 6 months. AI is entering the recursive self improvement phase, that roadmap is laying in front our eyes, what it can and would unlock is truly, truly unpredictable.
I am both intrigued and scared.