>In my experience this problem could be alleviated if it were possible for a worker to work a 50-60 hour week at a single job without incurring additional expenses for their employer.

How would working more without any more wages actually help the worker? Or do you mean the worker would receive their normal hourly wage without the "additional expense" of time-and-a-half overtime rates?

This scheme sounds insane, a recipe for slave-driving and exploitation of the worst kinds.