To get the six-track mix onto home video without any alteration at all, there would have to be a home video format that supported having five channels across the front. There is no home video format that does this, so it would be both impossible and pointless. The left-center and right-center fronts most likely only contain a mix of the LCR channels anyway, which was only done to fill in the space in a gigantic cinema environment. In a smaller home viewing space, there would be no purpose whatsoever to hearing this, for it would just make everything phasey and weird.

The extra front channels on 70mm not having any discrete information of their own is one of the reasons why, beginning with Star Wars, they were reassigned to the purpose of being dedicated low frequency channels instead.