They don't anymore, at least not the computers. When you let them start from normal starting position and provide decent hardware and some time it's always a draw and has been for a few years now.
No one is going to waste the CPU time running Stockfish (or GPU with Leela) against each other at classical time controls long enough to see a decisive game which might never happen anyway so we will likely never know. I think current Stockfish on a modern ThreadRipper with classical time control will never be beaten. I am not 100% sure I am right but I don't expect (but would love to!) to be proven wrong.
