This already exists, in the form of Android. Is it ideologically perfect? Maybe not, but it's more than good enough for most people. Android is widely adopted, it's available on many different devices, users can install their own apps from a variety of sources, and there's a fair amount of freedom for developers to choose how to implement and distribute their apps.
Jolla at one point claimed to have €200m in capital. This is probably some Nokia and some Finland government money. Crunchbase does not list VC investors, or any investors for that matter.