It seems to me that the choices really are that Republicans will achieve parity among Latinos — which probably depends upon getting them to identify with the whites and against the blacks — or else Democrats will have a general working majority, interrupted by recessions, scandals, and whatnot.
The point being that if you look at my generation, we’re pretty liberal irrespective of race. There’s clearly something to that. Then again, 2008 was a strong Democratic year across the board. The McCain-Obama split for whites under 30 is basically the same as the McCain-Obama split for the overall electorate. So if we assume that the “real” split in the country (controlling for recessions, Bush fatigue, etc.) is about 50-50, then what it takes for white people born in the 1980s to become a Republican-leaning demographic is for the GOP to moderate its views on gay marriage and for more 80s-born whites to become upset about income taxes. The gay moderation is already happening, and since people tend to earn more money in their 30s and 40s than they do in their 20s, I think the latter will probably happen too.
But before I speculate further, obviously there’s a huge wild card here around the future course of immigration policy. What we’re doing right now obviously doesn’t work, but there also seems to be no political path forward to change. But presumably something will happen at some point and whatever that “something” is, it’ll have implications both for demographics and for where Hispanics fit into the political system.