I don't buy it, sorry. The poorest countries have the most generous welfare systems. Just laser-targeted to the elite. (Western countries also direct much direct and indirect welfare to the elite and their dependents.) I propose that open borders are self-limiting in themselves, not via the proposed interaction with welfare. No one here agrees with my migration policies - except immigrants, who mostly don't want what they left behind to follow them. A critical mass of immigrants voting is the most certain and perhaps the only good way to end mass immigration, IMHO, YMMV
Productive immigrants tend to be against open borders, it's true. But open borders combined with a generous *universal* (I stand corrected.) welfare state will tend to be less attractive to productive immigrants (they don't need the help and don't want to pay for it), and more attractive to the least-productive ones (they like the free stuff and don't pay for it).
True enough, but perhaps not sufficiently so to prevent social welfare being useful politically. Social welfare here is far from universal; there are interviews, tests, social worker's discretion, and, for many categories, a race requirement. (Germany may be different.) It makes perfect sense when you view social welfare as a patrimonial system for vote-buying at the lowest cost. (Just as industry policy here is mostly grant-laundering at high cost). Elites can still use social welfare to buy new immigrant voters as long as existing citizens can be excluded from it. There is a level of economic disarray at which this will cease to draw, but the regime's other vital functions have probably imploded before that. I encourage both tax avoidance and tax evasion to accelerate this, I admit.