It's common to conflate the idea of source availability with problems encountered by lack of binary stable interfaces. One of the problems with the status quo on Linux isn't that drivers aren't released as source, but that they aren't upstreamed. This causes the drivers to no longer be valid very quickly. If you solve the validity problem, folks can continue to release drivers, alongside their source and they will continue to be valid even as the rest of the operating system evolves. Just because Windows drivers tend to not have source available doesn't mean that it's a given the same will be true for fuchsia drivers. It is ultimately product makers who use fuchsia as a platform who drive the incentives for what driver authors do with their drivers.