Why is it easy to implement any toy language that is buggy, not standards compliant and slow? Well that should be kinda obvious right? It takes 10+ years to mak

Why is it easy to implement any toy language that is buggy, not standards compliant and slow? Well that should be kinda obvious right? It takes 10+ years to make high quality implementations of Lisp that can compete with the best out there. Same with most (all?) other languages. With the exception of Forth maybe?