I've only seen new Unions end badly in places doing so.

Companies just move the work elsewhere. As now companies are often owned by bigger companies/have multiple operations. So it's much easier to do so.

Managers are often overworked/overpressured to perform, get by with less, competing with foreign companies with 'free' labor. And some Workers are jaded by the old Auto Factory days their parents worked. Makes for very toxic environments.