The enterprising Indian and Chinese citizen should know that it could be basically decades to immigrate to the US, so they're choosing anywhere else as a better substitute (or finding loopholes like gaining citizenship in other nations that don't have as long a waiting list?). Based on the current economic regime, it could be decades before candidates are granted permanent citizenship.
that is a bureaucratic hurdle that has little to do with the actual desirability of the USA as an immigration destination. The fact that so many Indians and Chinese nationals continue to move to the USA despite the immigration challenge is testament to this.
