"Wrong; it is. I already gave you a clue: falsification tests. Experiments are not the only way to test theories."
Please describe the falsification tests for the Big Bang.
This is probably the most celebrated one:
Near the 40s, there were 2 theories in the scientific arena regarding the origin of the universe. One of the them was the steady-state theory and the Big Bang theory. In 1948, George Gamow predicted that if the Big Bang theory was accurate, there should have been cosmic microwave background radiation, as a sort of afterglow from the expansion. In the 60s, Arno Penzias and Robert Wilson were doing a series of observations with a new microwave receiver from Bell when they received excess noise. They investigated further and discovered that they had found the elusive CMB.
That's a falsification test for the Big Bang theory.