Note also the profusion of low-paying jobs in retail and food service, in which workers usually have short careers and little chance of internal advancement. Such work is practically impossible to unionize. Meatcutters in grocery stores are an exception.
This isn't exactly what you were saying, but the proliferation of temporary, disjointed work (the "fractured workplace," as it's come to be called) and the difficulty of union organizing aern't disconnected. Any company who can scheme around the employee/independent contractor question will rationally do so if possible. Fed-Ex's entire employment structure is based around keeping out the Teamsters and flaunting labor law, for example.
