> If you think that the union isn't demonstrably an effective tool for having achieved huge increases in salaries for players across the board at both the highest and lowest skill levels, I'd argue the burden of proof is on you, because you'd be arguing against the obvious interpretation of the history in the decades following the establishment of the union.

The burden is on anyone to make a claim in either direction because you don’t have a control. How do you know the salaries wouldn’t have increased just due to baseball popularity and demand for good players?