Vulkan very much is designed to give flexibility to hardware vendors. Where abstractions do paper over differences it's generally where it makes the abstraction cheap in runtime but you might take more code vs. less code but requiring a feature that would be otherwise optional (for example some of the complex pipeline manipulation Vs bindless)
If the reason they don't support the features Vulkan needs in hardware is because they don't want to support them in software, the logic gets a bit circular.
I'm interested in which came first, or if it's a little of both.