I don't see how anyone can think Trump is a temporary phenomenon, it's been a decade since he got into politics and things have only gotten nastier. On the scale of a person's life, this is definitely not a temporary thing.
I see no evidence that Trumpism will survive Trump. To the extend that Trumpism exceeds the bounds of normal partisan politics, it's driven by a cult of personality. Once the personality is gone, the unique aspects of the movement dissipate.