[Taylor]

Especially in a manufacturing/logistics setting, the line between white collar and blue collar is becoming blurred. Traditional engineers are stepping outside the office for true experience and working side-by-side with the laborers to create solutions. Especially with the popularization of Six Sigma, Kaizen, and similar programs, traditional laborers are called upon to facilitate higher-level processes and decisions.
As far as the genesis of the blue-collar-jobs-are-undesirable notion, I'd look no farther than family histories. You don't have to travel very far to find a laborer who lives by the mantra, "I'm doing this job so my kids/grandkids don't have to."