There is no difference.
You might as well claim that a millennium is an impossibility as no one person has ever witnessed one in its entirety.
Sure days happen, we see that all the time. But there is no difference between a day and a millennium. They are both arrived at by incrementally adding a second a go, till you get to the destination.
Tic . one second
Tic . one second.
Tic . one second
Tic . one second.
Tic . one second
Tic . one second.
Each tic, a minuscule change that has little or no impact on the whole. But given enough of them, over a suitable period and you will get an hour, a day, a year, a decade, a century, a millennium. Huge changes through insignificant steps.
Evolution is the same. Micro and Macro are simply the Days and Millennia of biological change, one witnessed easily the other not so. They are simply names for different numbers of the same event. Essentially different units for the same measurement.
FYI:
1 minute = 60 seconds
1 day = 86 400 seconds
1 millenium = 3.1556926 10^10 seconds
Edited by ohnhai, : added the ^ SYMBOL