Python interpreter is known to leak its implementation (__class_ modification after creation, monkey patching with __getattr__, sys._getframe, eval/exec, deterministic call to __del__, no proper python API for libraries, etc.)
You have to plug all of those holes before having a chance to get a decent JIT. Otherwise it will be just another JIT attempt, like Psyco, Unladen Swallow, Pyston.
V8 predates strict mode, and handles all the exec/eval, monkey patching and object system abuse you can do in JavaScript just fine. Common Lisp is one of the most dynamic languages in the world and allows you to do ridiculous things in terms of meta-programming and essentially building domain-specific languages into your program, yet it too manages to have ahead-of-time compiled implementations that are very performant. Also PyPy exists.
There are definitely some technical aspects that make it hard to make Python fast, but they are not insurmountable. The reason CPython is slow today is simply because performance has not historically been prioritized by its developers.