Immigration from a country, as it increases, tends towards the norm. The first wave of Cuban emigres were the Americanized elite of Batista Cuba. As emigration continued, it ended up as Marielito criminal trash. Right now immigration from India is white collar professionals. Were it to continue at the same level it would end up as Calcutta street beggars. The same with Mexicans. As the volume of immigration increases, it will become poorer and poorer Mexicans.
Point taken....however, it is far easier for people from Cuba and Mexico to come here than it is for Indians.
The airfare from India to the US costs several times the average Indian's annual income. And, it is a long walk/swim from Calcutta to Columbus.