Google won’t be producing Ad Campaigns against GPL, no. Yet the licensing model of the Linux Kernel & the kernel developer policy towards drivers & driver interfaces effectively renders Android hostage. This complicates Android’s architecture greatly which is why they’ve spent exorbitant sums of time trying to ameliorate the damage.
Anyways, if you’re going to build an alternative or fork another stack —- you might as well hit two birds with one stone. Fuchsia’s relatively distinct capability-based, quasi-microkernel (it is not in fact a microkernel on a strict read) architecture is a chance to cleave off technical debt and start anew on security, and it’s relative modularity dovetails into the whole driver, kernel interface issue.