The problem with socialism is that it self destructs after a while.
In socialism, the "safety net" has to be constructed with funds taken from higher income people. This creates an incentive for them to go elsewhere, unless (like the USSR and East Germany did) you put up walls to keep them in.
Meanwhile, the unproductive people of the world will be trying to migrate to the places with the best benefits, unless you take measures to keep them out (like Trump is trying to do).
Eventually you have more consumers than producers, and things collapse. Like Venezuela.
I don't think people from third world countries are unproductive. they might have to work day and night just to get the air fare to go somewhere else. Their problem is that they get insufficient pay for their production. Not because of socialism but because of being used by factory owners and not being paid enough. They are the victims of market forces, capitalism not socialism.
Again you using Russia and East Germany to illustrate Socialism, Communism, not socialism.
Ask the many Americans who now live in the EU including the UK, they are very very happy to be here where the system is a bit socialist. Where they get operations without becoming bankrupt.