" and that's precisely what we want to avoid. IMO that;s one reason why the Python (and e.g. PHP) community has been so slow to implement good VMs. It has deferred to C code for performance-critical code _where it could_ (e.g. regular expressions) at the expense of rigid dependence on that external library. Now that companies such as Dropbox and Facebook are needing Python and PHP to exhibit good performance they are finally implementing faster VMs long after other languages. " nope , you are close but you got it the other way around. As a smalltalker you see it from purist way of view. For you Python is that language that got caught up on too reliance on C/C++ libraries. What you see as side effect is actually the central goal of python. The central goal of python was and still is to a great extend today to serve as scripting language for C and C++ code. This what made python so successful that a C/C++ coder could use on top of its app embedded inside its app. This why so many people use it even today. You also again wrong to assume that its a late thing that new VMs are developed for Python , PyPy which is very well known inside the python community has been around more than 12 years. Its a very performant JIT VM 2-10 faster than cpython. Why cpython has not ported to it ? because of not so good support for C/C++ , zero support for cpython libraries and of course because as they say it would complicate the development of cpython quite a lot . Its that situation that only a couple of people can decypher the magic of the VM and the rest of developer only hope for the best. And PyPy is not the only JIT VM for python , there is also Jython that runs of JVM and ironpython that runs on .NET and Mono. What those 3 have in common ?that are used by a tiny crowd compared to people using cpython. The truth is pure python libraries are a rarity . Why you think the most popular , by far, implementation of python is called cpython ? I will give you a hint, 50% of its source code is written in C. No thats not just the VM its libraries and cpython comes with a lot of libraries included. Frankly I dont believe that any VM ever however fast will ever beat smooth integration of C/C++ code unless you have a huge company to back you up with an insane amount of libraries. Java had Sun , .NET has still Microsoft. For people that speed is a serious matter even if a VM is a mere 30% slower than optimised C code, they will take the C code any day.