A good part of it has to do with community. Python and Ruby for the most part have no corporate backing. No one gets paid to work on Python and Ruby full-time (and they especially don't get paid to work on CPython or MRI the whole time). V8, on the other hand, is backed by the most powerful IT company in the world.

Furthermore, V8 can be faster because the only thing that matters to the V8 people is the interpreter -- they have no standard library to work on, no concerns about language design. They just write the interpreter. That's it.

It has nothing to do with intellectual property law. Nor is Python co-developed by Google guys (its creator works there along with a few other committers, but they don't get paid to work on Python).

Another obstacle to Python speed is Python 3. Its adoption seems to be the main concern of the language developers -- to the point that they have frozen development of new language features until other implementations catch up.

On to the technical details, I don't know much about Ruby, but Python has a number of places where optimizations could be used (and Unladen Swallow, a Google project, started to implement these before biting the dust). Here are some of the optimizations that they planned. I could see Python gaining V8 speed in the future if a JIT a la PyPy gets implemented for CPython, but that does not seem likely for the coming years (the focus right now is Python 3 adoption, not a JIT).

Many also feel that Ruby and Python could benefit immensely from removing their respective global interpreter locks.

You also have to understand that Python and Ruby are both much heavier languages than JS -- they provide far more in the way of standard library, language features, and structure. The class system of object-orientation alone adds a great deal of weight (in a good way, I think). I almost think of Javascript as a language designed to be embedded, like Lua (and in many ways, they are similar). Ruby and Python have a much richer set of features, and that expressiveness is usually going to come at the cost of speed.