Planets are consantly moving and are relitivly nearby so their movment has a big impact on our veiw o them but stars are far away so it take a huge amount of movement to change our view of them
I'm sure you've noticed that an airplane high in the sky, far away from you, looks like it's moving very slowly. At the same time, somebody passing you on a skateboard whizzes past you at high speed. The farther away something is from you, the slower it appears to move.
The nearest star outside the solar system is almost 32 thousand times as far away from us as the farthest visible planet (Saturn) is, and all of the other stars are farther than that.
That's why you have to wait a few thousand years before you notice that the shape of a constellation has changed.
To put it a slightly different way . . . Everything is in motion. The motion is more noticeable for nearby things, and less noticeable for farther-away things. Objects within our solar system are the only ones near enough so that a human lifetime is a long enough period in which to notice the change in their position. Even Pluto moves less then 1.5° against the 'background' stars in a whole year.
