Some models ( 520 , 620) didn't qualify for upgrade to W10 because their smaller memory (520 mb) , clearly it's not the case of Lumia 1020. I can speculate tha

Some models ( 520 , 620) didn't qualify for upgrade to W10 because their smaller memory (520 mb) , clearly it's not the case of Lumia 1020. I can speculate that they don't wrote yet some firmware or software module needed to address the particular capabilities of 1020's camera , just guessing...