In addition Ada allows dynamically-sized arrays to be allocated on the stack and to be returned from a function. Efficient implement of the latter requires rather non-trivial support on the compiler side and C/C++/Rust have nothing like that. Yet in many cases it allows to eliminate new/delete and simplify code.

For example, just consider if C allowed to return a plain C string from a function without any heap allocation. Things like unsafe sprintf/strcopy would never happen then.