OCaml's been around for 30 years, and will be around for many decades more. It's not this year's fad.
Right, because Unix had no effect on the number of people working in C.
> "It makes more sense to give the people the tools they need to get the job done"
MirageOS takes a clean-slate approach and it's not exactly a secret. There are evidently significant benefits to this, as well as trade-offs. There are other unikernel implementations out there that have prioritised legacy over safety and composability.
There is nothing particularly arcane about OCaml. The fact that it's not a mainstream language is not a good indicator of its complexity.
http://www.quora.com/Do-you-feel-that-golang-is-ugly/answer/...