Potential sales are irrelevant for their decision to look at PC first when most backers invested for a PC version. Those who might buy it on console could be more as those on PC (but not for certain) but they never backed them as much to realise the game so that they are obviously not the "favoured" group as long as the dev doesn't want to fool their backers just for potential higher sales on another platform.
It's a pretty fair decision to think first about your biggest group of backers and only then about the potential extra customers.