I agree with this. A smart coder is going to write it all in a high-level language and then profile it to see which tiny bits might be better off in assembler a

I agree with this. A smart coder is going to write it all in a high-level language and then profile it to see which tiny bits might be better off in assembler and then profile it again to test their theory. Modern compilers know a lot of tricks and can often find optimizations that would be hard to do manually in machine code.