Lack of parallelism will cause similar problems to what python faces due to global interpreter lock, killing performance. It is 2017 (almost), parallelism should be available in any new programming language.
Parallelism isn't easy, so the core team is expending time to get it done correctly and released before 1.0. Crystal doesn't have anything like the GIL, and the compiler already enforces some simple rules, like type flow not being available on instance variables because they could be changed on another thread. You can't expect the world from any new project straight away.
Yes, it will be available before 1.0. It's on the roadmap.
Parallelism is available to any language through fork().