I didn't say it couldn't, just that to do it right is very difficult.

Also, here's a better example of what I was saying before:

It is a 4K scan of a very good LPP 35mm theatrical print (that I'm told was done on a professional scanner, not a home built one - and it seems like it, since you can see the grain structure of the print well defined) compared to a 4K upscale of the BD - while at first sight, the print seems better, because the BD bears unmistakable signs of the upscaling, when you look closely, the BD actually resolves more detail on the skin.

And now imagine what kind of detail level could be achieved if they did a proper 4K scan of the original negative, when even a poor 1080p scan of the o-neg, that doesn't actually resolve much beyond 720p, can show more detail than a 4K scan of a projection print.