Sure, so you'll divide the codebase into neat little chunks and pay 100 programmers for 3 years to unfuck all the garbage code.
Tell you what, go to the hospital and get 9 women to give birth to one baby in 1 month.
Yes, it's a feasable task, especially for a gigantic corporation. However, it doesn't mean you can "just reverse engineer the code", because it's going to be an enormous task that is difficult to achieve and time consuming and probably intoduce new bugs.
On top of that, porting it to PC and not just a single piece of hardware adds even more complexity the original, single console only release, did not even consider, making it even more difficult and buggy.
It can be done, but it needs a lot of time and effort.