Idaho law lets your boss sue you if you get a better job

By your statement, I can only suspect that you assume the marginal decrease in a retained employee’s productivity due to unhappiness related to such laws is of a greater negative value than replacing the loss in productivity from said employee who freely leaves (because they are not under risk of legal threat) and the costs related to replacing them. Put another way, does the cost to an employer of making an employee “happy” result in productivity minus happiness cost that is greater than productivity at, say, no cost of happiness…?

While I don’t necessarily disagree with your assumptions longer term (that much should have been evident in my comment), happy worker to productive worker to profitable company paints with a broad brush, ignoring industry, geography, etc. I have first hand evidence that my wife’s former employer in question was very profitable, so much so that the owners sold for a tidy fortune over the long-term. But I’d be happy to read the studies to which you allude, as I have an interest in economics and would be curious to see how the happiness of employees is quantified and sampled.