I think working conditions have changed enough since then to make a request for non-biased studies a reasonable one. Most debates about unions seem to boil down to “I just know” or anecdotes. I would expect unions to fund research to show that working conditions are better in union shops, but not include the fact that some unionized shops can’t compete in a market with non union shops and might go out of business. (But have great working conditions until the last day) And vice-versa for pro industry research. Unions are adversarial, and feel necessary to people that view employment or employers through that lens. It’s possible that we can still credit unions with the status quo, but 1they have nowhere near the adoption of vaccines to make the analogy a good one. I’d rather debate “which employers/industries” need unions than debate whether they are objectively good in all circumstances.