“One eye”, in humans, has about 125 million sensors (120 million rods, 6 million cones) Calling that “one sensor” is cheating slightly.

But yes, you only need that second eye for stereo vision if you only have data from a single moment in time.

In theory, you can see perfect 3D with a single photoreceptor by scanning with it (giving up temporal resolution, a bit like a electron gun that can write a million pixels per second writes only 50 or 60 images a second on a tv)