That's partly true and partly not. In particular, if one anticipates returning to a pricey location later in life (e.g. needing to take care of elderly relativ

That's partly true and partly not. In particular, if one anticipates returning to a pricey location later in life (e.g. needing to take care of elderly relatives there), one has to save for retirement at a higher level than if one can stay in the cheaper place forever. Cost of living comparisons used to justify salary reductions rarely account for such scenarios. With that said, the numbers can still work out to make it a good financial deal, it's just less automatically true.