Browsers are already highly specialized and complex VMs. If you have the ability to build a browser and work on all parts of it, you have the ability to create

Browsers are already highly specialized and complex VMs. If you have the ability to build a browser and work on all parts of it, you have the ability to create new languages. So creating a new language is not at all that far away from their core competency. They are also working in a space where they have a strong need for a good systems language, so the motivation is there as well.