That's what I've been wondering - why don't the browsers add a few more scripting languages, like python? If IE didn't exist, Chrome and Firefox could do it, just for fun, they're very open to new features.
These days I'd be far less surprised to see Microsoft and Google co-implement something with regards to new scripting language support than I would be to see Mozilla get involved.
Mozilla is basically cultish about JavaScript's place as the One True Web Language.
