Probably because the older languages did not bring enough to the table versus C. I've notice that the trend of new compiled language is fairly recent with Nim

Probably because the older languages did not bring enough to the table versus C. I've notice that the trend of new compiled language is fairly recent with Nim (2006)/Go (2009)/Rust (2010). The previous trend was more oriented toward interpreted languages Python (1991)/Ruby (1995)/Javascript (1995). So maybe, 10 years is the maturity age and we will see more of those language used for Linux kernel development.