Experimental studies are based on

Experimental studies rest on the deliberate manipulation of an independent variable.

The researcher changes one variable and observes the effect on another under controlled conditions.

Being fixed on conceptual parameters only would leave nothing to manipulate or test.

Mere replication of past research repeats studies without introducing a new manipulation.

A survey of existing literature reviews prior work and manipulates no variable.

Manipulation plus control over extraneous factors is what allows causal inference.