Maybe not directly - my guess is that they want to get rid of the Linux kernel: the Linux driver model leaves Android upgrades held hostage by OEMs and SoC manufacturers who are incentivized against old phones getting OS upgrades (planned obsolescence).
With Fuchsia, Google has a clean slate and can choose to have 'write-once' drivers with a stable driver interface across kernel/version upgrades.
Writing once-off proprietary drivers for Linux is equally easy, no more, no less. Proprietary Linux drivers have the added downside of not supporting later kernel versions.
With mobile, as things are, you're guaranteed to have a bunch of proprietary drivers. With the Linux kernel, all the modules need to be the same version of the kernel because you can't guarantee that the interface hasn't changed. Contrast that with Windows, where the same driver file will install and work with a wide range of actual Windows kernel versions.
If Fuschia provides a stable driver interface, then it would mean that my 5-year-old phone doesn't need to also use a 5-year-old kernel to interface with its closed-source drivers. It'd be a big win, overall.
That seems like perfect being the enemy of better. The realistic options aren't "stick with current model of closed drivers locked to specific version of open kernel" and "force hardware manufacturers to produce open drivers". That second one isn't going to happen. The best you'll get is an open shim and a closed blob.
It's a retreat. It could have happened. The ground was ceded when closed source drivers were allowed to be willy-nilly linked into the kernel with impunity, a clear GPL violation.
The Free Software initiative requires bravery and confidence. The idea is that if you establish a large enough base of viral software, people will eventually have no choice but to become a part, or be put at great disadvantage. And it worked. Linux is everywhere. The only places it didn't work, are the places we were too cowardly to press the advantage.
Stallman was right. You cannot compromise. Once you start paying the Dane-geld, you'll never get rid of the Dane.
I'd agree if it wasn't Google we are talking about. With the Open Handset Alliance they certainly would have the power to force hardware manufactures to produce open drivers.
I agree that they'd have the power to do it. I don't think they have the motivation, though. It's a clear win for the customers, but a lot of work on their part that I don't think would translate directly to numbers on earnings reports.