An $80 packaged game on a shelf probably nets the developer the same profit as a $20 digital version of the same game delivered via Steam. Packaging, distribution and retail markup are a big chunk of the price.
I assume a motivations of it are a) to have presence next to console games and b) gift-giving? If there were at least the basic versions of the games on the disc, you could add c) people with slow internet to the equation, but that seems less and less common.