The US, despite being more "tech mature" than other countries, still fails to provide work/life balance or maintain quality code. I was honestly surprised to see these two things at the top of every list. It seems obvious that companies would prioritize these two things, yet... they aren't the standard.
Just reading the other popular posts on HN today (ie. https://medium.com/@deusexmachina667/you-fired-your-top-tale...), it sounds like these are common stories. You can be well-respected, be incredibly experienced/knowledgable, and still be overworked and pushed to push code we're not proud of. These things lead to turnover. I wonder if the startup culture in the US ("grow as fast as you can, do whatever it takes!") is especially bad, and contributes to low retention. Probably.
For instance, I've seen in-house codebases that drive US devs to anger about their low quality that are regular paragons of excellence compared to stuff that's come back as part of outsourced projects (and not solely offshores outsourcing), so it's all relative.