This is a false dichotomy. You can have massive parallelism and determinism. You can trade determinism for convenience, but that doesn't make things easier: no

This is a false dichotomy. You can have massive parallelism and determinism. You can trade determinism for convenience, but that doesn't make things easier: now you have to deal with the determinism. But to suggest that massive parallelism somehow implies non-determinism is quite disingenuous from my perspective. We have mutexes and lock-free ring buffers and stable sorts and all sorts of bells and whistles to make parallelism safe elsewhere. We also already have tools to solve this for GPUs.