jjmafiae wrote:How many people still run systems that are older than 7 years?
What's important is that Mantle only runs in Windows on AMD video cards made in the last 2 years, DirectX 12 won't be released until next year, Metal only runs on iOS on iPads and iPhones released in the last 9 months, and OpenGL 5 isn't announced yet and will likely have similar requirements to Mantle (or DirectX 11 / OpenGL 4 at the very least.)
love.graphics wouldn't really benefit much by making use of any of the capabilities specific to the systems listed above, and adding a backend for one of the new APIs would make all of love.graphics harder to maintain in the future, so there needs to be a really good reason to spend all that effort and time (it would really be quite a lot of work to do.)