2006 : Bush will be the last republican president ever
2008 : Obama has created a permanent democratic majority
2012 : The GOP is doomed unless they pass an amnesty bill
2019 : The GOP will die, Trump will be the last republican president ever and the USA will become a socialist country
2006-2018: GOP gains among Millennial and Gen Z voters: ZERO. What do y'all expect is going to happen? That old people won't die, or a ~30% deficit will reverse itself overnight? Nah, you're digging your own grave. Let's not forget that your current bases of power — the EC, the Senate, and the Supreme Court — have no democratic legitimacy.
I don't know what will happen in the future, but the idea that the GOP will become irrelevant and the USA will become a one party country is dumb. Concerning your question, I don't expect liberal millenials to suddenly become conservative but the 30% gap will likely reduce itself over the time, just look at the Generation X, in 2006 these voters who were between 25 and 40 years old favoured Dems by 30, 12 years later these voters (who are now between 37 and 52 years old) favoured dems by a far smaller margin (people between 40 and 49 voted D 52/46). Then you have boomers who are now between 53 and 73 years and who still have between 15 and 35 years to live and who are becoming more R friendly over the time.
