The evolution of a way of speech

Now:
"Rome was not built in one day"

During the roman empire:
"Rome is still being built - and apparently it's taking more than one day"

In the stone age:
"Rome has not been built yet - but building it will surely take more than one day"

In the jurassic period:
"If we pterodactyls shall ever become extinct and a species named homo sapiens shall evolve, who will build a group of houses and call it Rome, it will most likely be a project that will take more than one day"