Link in OP doesn't work for me.
White men have been the bedrock of Republican party for decades. The issue is as a percentage of the whole white men are becoming lower from silent (40%) to boomer (36%) to X (31%) and now millennial (28%).
The three groups Republicans win with are the elderly (silent and boomer), white men, and religious. We've had an era (1980 to present) where this was a winning coalition. The question for Republicans is can they adjust to a new landscape that is less white and less religious with each election cycle.