[raimue]

Back then, your suggestions were niche languages (and some still are) and are still not popular for embedded systems or network equipment. Large runtimes or huge static binaries are not suitable due to the memory and storage constraints.

You have to consider the surrounding ecosystem. Those interested in such languages are not necessarily those interested in contributing solutions to the problem space. Any project attempting to use such a language in OpenWrt would very likely not have survived until today.