Back in 2006 a lot of  NRI sold everything in us, aus,uk and went back to stay in India and work. Do they have dual citizen? No. 

The same time housing market start collapsing all over us,  uk. 
I think south Korea also does not allow dual citizen. South korea is also developed by their non residents. Nepali NRN lai desh ok Banda personal benefit nai badhi chahine. Kati facility chahine. Alikatita ta afule pain sacrifice garna saknu parchani yedi desh ko testai maya cha bhaye.