I wish it were true that when they become economically successful they quit voting Democrat, But many will stay with the party, and it's for that very same reason you'll find so many Italians, Jews and Irish voting for Democrats. When their grand-parents got off the boats, the Democrat ward bosses were there to help them get work, find a place to live, and in return, get their votes. This wasn't done by government spending, but by politicians building their bases. And it was in sharp contrast to what the immigrants perceived as the greedy business owners.
This sort of thing tends to make people loyal for life, and we've seen that played out for the past 80 years. Even though the Democrat voters continued to move up the economic ladder, they have the memory of their sainted Grandmother voting straight Democrat all her life, and talking bad about the business owners of her day, who were likely Republican.
I can add to that.
I know non-white immigrants here in Maryland who went to college (free naturally) then got a government job and they worship Obama as being like them. I mean it's Jim Jones worship. And one black immigrant who worships Obama told me that illegal immigration is nothing more than paper-work and that American blacks are lazy and don't want to work so we need illegals to work here.
Surprisingly I know black cleaning lady (yes a woman) who is real African American, roots in this country, who voted against Obama twice. She has told me many times that she thinks Obama is a con-man who doesn't know what he is doing.
And she doesn't like illegals being put in front of the line. I wish there were more blacks like her.
If Republicans were smart (which they obviously are not) they would split some of the Dem groups apart and play them against each other.