Nvidia had a driver for Vulkan for Kepler which launched in 2012, AMD had support all the way back to GCN 1.0 (also 2012). Intel did have issues supporting it, I can't recall if it was for hardware reasons or just lack of desire for a driver.

Vulkan has substantial advantages for multi-threaded code, as well as exposing the underlying asynchronous nature of running code on the GPU. The kind of thing you want to be able to control with a desktop compositor where controlling vsync and present timing is very important.