Metal gives no choice for the lower level. Something higher level built on Vulkan with ability still to use the lower level for those who need would be the successful execution. Metal isn't that, besides being Apple only anyway.
I.e. I'd agree with your idea if Metal was actually built by Apple on top of Vulkan as a convenience abstraction and you could use Vulkan there directly too.
The first Metal version didn't provide much low-level access, but the later Metal versions gradually added more low-level, more explicit features. The key point is that those features can be ignored if the higher level and more convenient features are good enough.
But I think the parent comment's point is just that if you start with low-level, you can always build on top of it, but the other way around you have to wait for the API vendor to give you the low level access you need.
I hear that you are saying Metal does a better job of being a convenient graphics API than Vulkan. I am just having trouble parsing why this would be an objective problem with Vulkan, rather than you just not being the target audience of this API.
I think the general idea was the right one, the execution of that idea was the problem (e.g. Metal is the successful execution of the same idea).