Tax reform of some kind will pass because the Republican Congress needs a win. Tax reform or cuts is something they've succeeded at it in general.
If it honest to God fails this Congress is beyond incompetent and Trumpy is a Carter figure. (Well he will be an incompetent one term President but that's probably not related to failing to cut taxes).
If Trump becomes a Carter figure could you see your timeline playing out faster than expected with 2020 being the realignment year?
Not necessarily. A crisis has to happen.
P.S. Steve Bannon is a fan of the “Fourth Turning” by Howe and Strauss.