There has got to be a national debate as to whether we want to turn this trend around; of course, we'll be labelled racists for raising the issue.
So many things are different that it’s hard to follow the parallel this article is trying to make.
As you say, the demographics have changed considerably. Also, the percentage of people on the dole. Also, the dedication of the media to be a propaganda arm for the Democrats. Not to mention McGovern was a challenger, Obama is an incumbent.
I think this article is grasping at straws to make its point.
What may happen is 1) war with China leads to an explosive increase in American robotics and automation, 2) after the war we no longer need cheap immigrant labor because the robots will work for less, 3) automation will happen in law enforcement leading unfortunately to a police state. No one will be here that shouldn't be here, 4) people inclined to raise children will displace the vain/envious/selfish leftists that are breeding themselves out of existence.