I think the single biggest reason Fortran is so successful in HPC is its implementation of multidimensional arrays. They are at least as fast as pointer arithme

I think the single biggest reason Fortran is so successful in HPC is its implementation of multidimensional arrays. They are at least as fast as pointer arithmetic style C, they have powerful splicing syntax and they have a simple but good because length checkable file output format. Teach a scientist all the imperative control flow constructs along with this and he knows how to program a cluster for data parallel tasks, the most common one in HPC. Concerning Haskell and Co: Get back to me when it's simple to do a performance analysis, e.g. roofline model. Julia on the other hand is promising, but it's still going to be an uphill battle w.r.t. the work gone into Fortran compilers.