Before I left the Smalltalk part of my career behind, someone had the occasion to compare the parser-compiler of one Smalltalk which was implemented in C with Yacc/Lex with one implemented in pure Smalltalk with a JIT VM. IT turns out, once the console logging was disabled, the JIT VM's parser was just as fast as the one in C.
In my experience of almost 2 decades, it has been a constant that uninformed programmers are especially uninformed about the relative performance of managed languages.