It is an immutable fact that the Constitution is the law of the land, but the law of the land should not be presumed to be immutable.
No artifact of the human mind can be maintained intact like a formalin-preserved insect on a pin. No matter how much comfort it would give us to have predictability and certainty in our law, the elements of human curiosity and cussedness would always give rise to unpredictability and chaos.
This introduces the possibility of improvement, whether through design or through accident, but it also raises the spectre of decline, whether through stupidity or sabotage.
Improvements have come in the form of amendments that accomplished the abolition of slavery and giving women the right to vote. Those were both long overdue by the time they passed.