Why is the proper motion of distant stars imperceptible over a human lifetime?

The slow physical shift translates to an apparent movement too small to detect

Stars do possess actual movement across the celestial sphere relative to our Sun, a movement technically known as proper motion. However, because these stars are situated at extreme distances—measured in light-years—even a relatively slow physical shift translates into an angular movement across the sky that is far too minute for the unaided human eye to notice across the duration of a typical human lifespan. This perceptual stability is what allowed ancient civilizations to use constellations as dependable navigational markers and for creating consistent celestial maps over millennia, relying on the stars seeming utterly permanent from our perspective.