The workers have no incentive to work harder.

Literal

Workers [to-たちには] more work [volitional-おう] [quotative-と] do stimulus [subject-が] nothing not-exist.

~ようとする刺激 ('incentive to try to do'). なにもない ('there is nothing at all') — a bleak statement about motivation. The volitional + とする pattern marks the intended action.