I am not familiar with that particular one but I have used other supercomputers and those people are not waiting for better hardware, they are trying to squeeze

I am not familiar with that particular one but I have used other supercomputers and those people are not waiting for better hardware, they are trying to squeeze the best performance they can out of what they have. The end result mostly depends on the balance between scientists and engineers in the development team, it will oscillates between "this is python because the scientists working on the code know only that but we are using MPI to at least use several cores" and "we have a direct line with the hardware vendors in order to help us write the best software possible for this thing".