Not all of these are the same. Since when is FP a fad? Would you say that structured programming is a fad? Is garbage collection?
In contrast, static versus dynamic typing doesn't seem likely to be so cyclical given the significant improvements in usability for gradually typed systems. Dynamic typing became most recently fashionable when the experience of using statically typed languages was sometimes unpleasant. Static typing has improved to the point where even retrofits onto other systems are very very good.
In areas where a reasonably complete gradual typing solution has emerged for a major dynamically typed language, it's rapidly become or becoming standard practice--Python and TypeScript being the two most obvious ones, but not the only ones. (Ruby may not get there. Its core implementation doesn't seem great. I wish they went with Sorbet.)
I don't see a reason that would unwind to the point where it's a serious conversation again.
(To say nothing of Excel as the most widespread functional reactive programming tool, but few count it as a "real" programming environment.)
Many mainstream ideas are incubated in the fp world, and wind up in the mainstream. for exmaple: GC, closures, higher order functions. but not any of the "functional programming languages" themselves.
> but it never seems to make it to the mainstream