alt Hacker News> they'll just use different features from it in addition to having different algorithms and architecture.
...so you'll have different code paths for desktop and mobile anyway. The same can be achieved with a Vulkan vs VulkanES split which would overlap for maybe 50..70% of the core API, but significantly differ in the rest (like resource binding).
But they don't actually differ, see the "no graphics API" blog post we're all commenting on :) The primary difference between mobile & desktop is performance, not feature set (ignoring for a minute the problem of outdated drivers).
And beyond that if you look at historical trends, mobile is and always has been just "desktop from 5-7 years ago". An API split that makes sense now will stop making sense rather quickly.