Vulkan has a very high initial cost when it comes to lines of code. You have to recreate a lot of stuff that you took for granted in OpenGL, such as a default framebuffer to draw to. Also, a lot of boilerplate code to create resources can be abstracted away into functions to reuse later. So while you might need a lot of lines to even draw a triangle, you won't need many more lines to draw a full 3D model.