> My money is on better work conditions being a better investment long term. It'd reduce turnover. Less time hiring/training new employees, and the employees you keep are happier, stick around longer, and become more efficient at their job through experience.

You might have noticed that most companies don't care about these things, because it doesn't matter much for them. For software engineers or equivalent, sure it matters a lot, but for unskilled workers that needs minimal training? Then it doesn't matter much, as even today we see that basically no company cares about their minimum wage workers conditions.