Of course, it's not necessary to use a language where "Give control of your phone to remote attackers" is one of the possibilities at all.

General purpose languages, whether that's something like C or Rust or even Javascript are not the appropriate tool. Turing Completeness is a bad idea from a security point of view, not a wonderful feature.

That's like asking whether it is the lack of a seatbelt that was the issue after sometime died in a car crash.

Well, of course the real issue was the car crash. But wearing a seatbelt would have sure helped!

Well, theoretically all can be secure (in regards to buffer overflows etc). Some just forbid to shoot you in the arm. And head.

Yes, almost all of these major exploits are memory safety related and would be mostly impossible in a memory safe language.