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.
Due to alpha-beta cutoffs, you don't need a full game tree. But if you did build a tree with all legal chess positions, it would have approximately 4.8x10^44 of them [1].
I am not saying Stockfish is going to solve it. I am saying it will not lose from the initial position. In other words my hypothesis is that we already have a soft solution to chess available. I can't prove it but I can proceed accordingly in practice (in opening preparation or correspondence games for example) and no one will prove me wrong or exploit it.
