[johnnyanmac]

Probably due to pricing parity agreed upon by physical retailers. You're right in that they should be cheaper, but Walmart/Gamestop et al. were smart enough to negotiate that early on in digital distribution. For the same reason, many early Steam releases was not beholden to this and thus cheaper.

Nowadays, there's enough market capture that they can simply charge the same amount due to greed, though. But there are early reasons for that.