[1] https://www.etk.fi/en/finnish-pension-system/pension-securit...
Calculator https://www.tyoelake.fi/sv/pensionsraknaren/
So far I am not sure how easy it is to get to 4K/mo.
But my point was more about you mentioning retirement savings only for US workers. While median income earners will get very similar government pensions in both countries.
Similarly if you move there from a country with lower taxes/pensions such as the US you’d probably bring savings to compensate that you missed a number of years.
After all, these pensions based on number of years worked is often just a form of mandated savings from employers payroll taxes.
If this 4K/mo is easily achievable only if you have another pension from a more generous country, then it is not proving your point much.
Take home pay in the US is college money, rainy day money, retirement money... Can't really compare take home pay in a welfare state with US take home pay. It's just not possible.
Now: if you plan to retire in the US, obviously your equation would be slightly different. Paying for an education in the US, then moving to a place where salaries are set assuming people get good pensions and free education, then moving back to the US where you again need retirement money - that's the tricky equation.