Abandoning your entire life and moving to another country is hard and it takes a huge toll on your mental well being, especially as you start approaching your 30s. And it just plain makes life harder, when the circumstances are hard enough already. And all of this for what specific benefit exactly? This aspect is so ingrained that, for example I see job ads, where they say, "to be eligible you should not have spent the last x years studying or working in this country". In fact let me quote:
• Must not have resided or carried out their main activity (work, studies, etc.) in Germany for more than 1 year out of the last 3 years. This is in line with standard mobility criteria for a standard Doctoral Training Network.
And then a couple of lines below they boast about a family-friendly environment, and how they prioritize disadvantaged individuals, without a hint of irony. It is neither family-friendly nor a suitable position for disadvantaged individuals if you force them to move away from their support networks to a foreign country.