It is very unlikely. Vulkan and OpenGL are two different paths. They will continue to coexist for many years to come.
He's just saying that because Khronos has actually done that exact thing before...
They were supposed to ve working on a new, modern, clean API called Longs Peak, which would break backwards compatibility with GL. And , after setting the hype train in motion, they released a new GL instead (and handed API war victory to D3D on a silver platter).
If they did the same thing this time, my bet would be on Valve taking to initiative to finish Mantle/Vulakn/Valven on their own, and form a new comittee making Khronos redundant. So, failure is not an option for them this time.