Unions haven’t gotten anything management didn’t give them since Truman. Truman pretty much promised the companies the union wouldn’t hurt them, and privately may have threatened them.
BS. Truman was a long time ago. None of the crap like the 'jobs bank' was a management idea. Management didn't give the unions their cushy contracts out of sheer good will, they were forced into it by strikes and threats of strikes.
They only reason management went along was that the contracts covered all US car makers, and so it didn't hurt them relative to their domestic competition. But the union rules stifled innovation on the production line, and raised the cost of a car. That left a lot of room for the overseas car makers to move in.