The history of the forty hour week stretches back a lot further than WWI and unions are a lot more powerful than you’re giving them credit for. Now, unions have a good portion of that power because violence is never fully off the table - but the blood spilled for American labor rights was mostly spilled by Americans at the hands of Pinkertons. A lot of other countries saw the writing on the wall and adopted those rights peacefully, but there are a lot of famous labor actions that happened in places other than Russia. The toppling of the Tzar certainly helped, but I think you’re giving it too much credit.