Sure, but they could logically glue a physical ethernet port onto the USB bus on a zero the same way it's on the USB bus on a 3B+... The BOM cost would be what

Sure, but they could logically glue a physical ethernet port onto the USB bus on a zero the same way it's on the USB bus on a 3B+... The BOM cost would be what, a few dollars at most for a cheap 8P8C jack and the ethernet chip.