The GOP's problem is less a generational one and more a racial one. The generation gap is only as wide as it is because Millennials are so much more diverse than the Silent Generation. The gap between white Silent Generation and white Millennial isn't that big and is liable to close a bit, but the GOP has shown no signs of being able to win minority voters of any generation.
True, but your post downplays the GOP's problem with young white millenials at least a little more than I would. Pew shows a 2 point GOP advantage among white millenials, while the GOP has at least a 9 point advantage with whites among each of the three other generations.
http://www.people-press.org/2015/04/07/a-deep-dive-into-party-affiliation/
