Say what you will about Hungary but I think it came up with some great incentives for future parents: income tax cuts. If you have 4 kids you don't pay income tax for life.
Using foreigners to fill a demographic shortfall is unsustainable/shortsighted.
That said, I'm in New Zealand and too many young adults emigrate because (A) our economy sucks and (B) richer economies like to employ NZ citizens (NZers love international travel/work).