There's nothing requiring functional languages to abstract away from the bare metal. For example, read up on Typed Assembly Language (TAL) -- it's a typed, func

There's nothing requiring functional languages to abstract away from the bare metal. For example, read up on Typed Assembly Language (TAL) -- it's a typed, functional implementation of x86 assembly. I think the main reason functional languages are currently slower, in general, than procedural languages is that they haven't been popular for long enough yet to get all of the necessary optimizations implemented in the compilers. Think about it -- millions of person-hours have been invested into implementing optimizations in C and Fortran compilers over the past few decades. I expect the performance gap will get shrink steadily as time goes on, and as you said, at some point a cost/benefit threshold is reached where it makes more sense to switch to a functional language even if it's a little slower.