There’s never a time where players can’t interact - just passing priority or putting triggered abilities on the stack are actions. And each time this could happen the game checks state based actions to see if someone has won. That said, if both players have no options or just pass (which is more pronounced online) then you can end up in inescapable loops that cause draws. A classic example is this Luis Scott-Vargas game:

https://youtu.be/AGXG5rNe_tI?feature=shared