I think if it was possible to configure the universe (time included) in the exact same way, save for a single variable, that would be the _only_ way science experiments would be done.
We almost have the ability to do that with software, but we just don’t most of the time.
That’s okay for many applications, but not all of them.
The standard that real world experiments are held to to qualify as "reproduction". Your hypothetical is interesting but it's clearly a different standard from what we actually use.
I think if it was possible to configure the universe (time included) in the exact same way, save for a single variable, that would be the _only_ way science experiments would be done.
We almost have the ability to do that with software, but we just don’t most of the time. That’s okay for many applications, but not all of them.