There are two schools of thought about the resilience of time. The first is that time is highly volatile, with every small event altering the possible outcome of the earth's future. The other view is that time is rigid, and no matter how hard you try, it will always spring back toward a determined present. Myself, I do not worry about such trivialities. I simply sell ties to anyone who wants to buy one...
Many writers make the mistake of making their readers appear like Lazarus, without any iota of care, throwing down books to readers to crunch as if they are dogs.