A secret of rock solid concurrency is communication, but there are many sane concurrency models. Consider people are already fast efficient safe sane code over hundreds of cores on GPU's which looks nothing like Erlang. Still, when you actually start to care that your concurrent code is accurate not just FAST you need to validate your calculations and Erlang does little to help you there. So sure it's better than C, but turn up the memory errors and it still falls down hard.