Because none of us live long enough. Even a few centuries of observation is not enough to notice the movement of most stars. In fact, there is only one star for which any movement might be noticed over the course of a very long life; Barnard's Star, sometimes called the "runaway star".
Barnard's Star is unique not only in that it is quite close to our Sun, as interstellar distances go, but it is moving much faster than most other stars.
To observe the stars, you would use a telescope.
At the Age of Exploration they used telescope to observe stars.
If you get the opportunity to observe through a large telescope then you may be able to see some of the larger asteroids in the belt. However this takes time, over a few nights as one mist observe the asteroids moving against the background of fixed stars. Usually astronomer use photographs to observe these movements.
It is impossible to happen. nothing is impossible
nkhhjh
They were there, above their head most nights - they could not help but observe them.
telescope
determine which stars are gravitationally bound to each other
pipi
The actual motion of stars is very hard to see because stars are very far away.
You use a telescope to observe stars, and sometimes also use a star map.
Galileo