>but what's the point of incrementally optimizing perl, MRI, or CPython when the result is still going to be an order of magnitude slower than SBCL, LuaJit, V8, or CogVM?
because you can't write Perl or Python for SBCL, LuaJit, V8 or CogVM.
because you can't write Perl or Python for SBCL, LuaJit, V8 or CogVM.
Compatibility with the massive ecosystem of existing code is something everybody who says "just rewrite the runtime with X" seems to forget.
It may also be that Perl 5 has always more or less had one implementation and has all kinds of messy parsing rules, so nobody bothered to complain since we all knew it was a disaster trying to sort that mess out.