The Fuchsia code itself is open, and while a vendor could make changes and not release them, a project like Pine wouldn't do that. That would indeed be a major motivation to use a Pine-like over other vendors.

> The Fuchsia code itself is open

For now. It doesn't yet have all of the proprietary bits added in, nor has it been shipped to OEM devices using mobile device hardware. Most of the proprietary Google bits of Android are proprietary by choice, there's no way Google is going to be any more open with Fuchsia.

Pine does not contribute device drivers, the SoC vendors and groups like Linaro&Collabora write them primarily.

Hopefully SoC vendors and IP vendors release the source for their device drivers.

Just like Darwin, the open source kernel of iOS…

pine64 and purism are lot smaller than qualcomm and the like. They don't have that type of leverage.