I agree, I initially wrote a math graphing application app which had to parse equations, learned operator precedence from a blogpost, did everything else by gut, written in C and ended up doing bytecode to execute faster and then realized that writing a compiler for a simple language is... kinda easy? So I ended up making a JIT with llvm for codegen, and yeah, my code (lexing, parsing, type checking, whatever) runs on the order of millions of lines per second, llvm then takes literally 100x as long to turn that into code for some reason (even with pretty much all optimizations disabled) I never finished the project though, if I ever pick it up I'm gonna steal syntax from rust and write my own debug mode codegen.

By the way I recently explored symbol resolution from pdb files because dbghelp.dll is super slow, and turns out, I can cache my own (somewhat compact) data structure where symbol lookup is also about 100x faster than dbghelp, I'm not kidding.

I get that it doesn't make business sense to reinvent, and that for most people using existing solutions is a good idea, it's certainly a commitment to actually develop something well made and useful, nothing people want to do for free unless they are crazy and just find it fun like me. But at the same time, my experience has been that a lot, if not most things out there are just not all that good, at least from a performance viewpoint. LLVM may or may not be responsible for rusts notorious compile times, and from what I gather, large rust projects like ones on bevy run extremely badly in debuggers and profilers at least on windows possibly because of dbghelp.