Its the lens, not the sensor, that determines exposure and depth of field

The debate about equivalence simply will not go away, so I've come up with an example that I think will make it much clearer. Mount a 50mm 1.4 FF lens on a D600 ff camera, take an image @1.4 of a subject somewhat off center that shows shallow depth of field and bokeh thats so popular these days. Now take three centered crops of the image; a APS DX size, m43 size, and a Nikon 1 size. All three images will have a different composition but exactly the same exposure and depth of field. Now take that same FF lens , mount it on a D300 APS sensor size camera, and, with adapters, an m43 OM-D and a Nikon 1 camera. Take the same subject image at the same distance @ 1.4 with the three cameras, and you will get exactly the same images as the cropped ff images. Despite different sensor sizes, they will, I believe, have the same exposure and dof. So a Nikon 1 small sensor camera can have the same shallow dof as a D600 ff camera, as long as you mount a ff lens on it.
So I believe its the lens, and not the sensor, that determines exposure and deph of field.