The most important thing is comprehension. If something is too long and the length makes it less readable then it is too long.
But if having 3-4 files open at the same time makes it harder for you to comprehend a single file because you can't get the full picture, that's on you.
I think it's more correct to say that we don't know how to travel in the other direction on the time axis. It could also simply be our perception of time only works unidirectionally.
From a mathematics point of view, nothing is preventing going backwards in time... We simply don't perceive time that way.
Practically, this does nothing for us.