It's not as complicated as perceptions of new media or paradigm of DD.
It comes down to price. The pricing of DD is out of whack with the costs.
Meanwhile physical media, as long as it can be re-sold, has an effective lower price. You buy for $60 and after you're done, you can sell it for $40 say, so you can buy more games with the recovered money, reducing your price for the next purchase.
Just on principle, nobody should pay $60 for the DD version, when the physical version cost them so much more to manufacture and distribute.