Demographics, most likely, will really help Democrats. But it's an extremely slow process - it will take 2-3 dozens of years for it's effects to be fully politically felt. Even for those. who are 18 today, it's a very long time. For those (like myself), who are somewhat over 50, that may be whole remaining life... At the same time Democratic collapse among whites (and not only in South, but in many ethnic AND/OR workingclass AND/ON small town/rural areas like Western Pennsylvania, SE Ohio, most of Indiana, Southern Illinois, parts of Missouri and so on) gives very big
tactical advantages to Repblicans. Strategically these people may be "dying off" and Democrats (i repeat) may be in better position, but tactically, IMHO - not so.