1080i is the same resolution with the same pixel content, but missing 50% native data
Unless I have forgotten something, this is not quite correct unless you add "in any given frame" to the end of that sentance.
Any interlaced signal
should contain all the data, just spread over two frames. Deinterlacing simply takes the two frames and merges them back into one frame with all the data.
So a progressive signal gives you all the data 60 times per second, an interlaced signal gives you all the data 30 times per second, but split over alternating frames.
