In current generation language there is definitely a trade-off between language productivity (i.e. speed of writing) and features such as speed and memory-safety.

So far we haven't been able to close this gap fully with current compilers and interpreters (i.e. python still runs slower than C).

It seems like that gap could be closed through, for example, automated refactoring into a rust-like language during compilation, or directly into more-efficient byte-code/ASM that behaves identically.

And surely if that is a possibility, that would affect language design (e.g. if you can abstract away some complexity around things like memory management).