It depends on the type of white collar job. Collective bargaining, in general, assumes a degree of fungibility that doesn't exist with all white collar position

It depends on the type of white collar job. Collective bargaining, in general, assumes a degree of fungibility that doesn't exist with all white collar positions. Two different managers, for instance, can have profoundly different consequences on a company's bottom line. Treating them as equal in that situation is hard to justify, to the company and the workers alike. That's one of the reasons private-sector unions have had so much trouble trying to unionize professionals even though they've been playing up their efforts for years now.