Similarly, the line worker is likely (correctly) to believe he won't be paid much more if he works harder, so his primary incentive is to just reduce his overall workload as much as possible and still get paid.
The best solution (and I believe a bunch of research backs this up) is to better incentivize your line workers and reward them appropriately. I know one study in particular that showed broad-based stock option ownership among employees was correlated with stronger company results, while options concentrated just among senior execs was not correlated with business success.