Interestingly you didn't mention Lua. The best Common Lisp, Smalltalk, and JS systems are always about a factor of 2 to 10 slower than C. This is not very good evidence for your assertion. (I suspect that's true of Dylan too, but haven't tried it.) By contrast, LuaJIT often beats GCC on performance. This is excellent evidence for your assertion.
Typically I measure CPython at about 40× slower than C, and SBCL, V8, and the like at about 2–10× slower than C. What cases are you seeing where those runtimes are hundreds of times faster than CPython?
People don't normally update to new versions of Lua, because they're not backwards compatible; it's not like Python or JS. WoW is still using Lua 5.1, as is MediaWiki. It's unlikely that this will ever change.
Probably at some point someone will continue LuaJIT development. It seems as likely that they will diverge in a different direction as follow PUC.
Right! When your hot code is in C you get a performance mix. Still, only about 3% of your logic has to be in interpreted Python for it to dominate your runtime.
