The only reason for such a discrepancy between physical and digital is because of copyright law, nothing more. To put it into perspective, you bought Playstation All-Stars(the first title that popped into my head that is physical and digital), for $59.99 at your local game store on the day of release, but it is also priced at $59.99 on PSN. Say you held off for 9 months waiting for the price to drop. It would be $49.99 at your store, but still $59.99 on PSN. How do you explain the price?
UltraDavid, a respected lawyer in the fighting game community, said about a year ago that the issue isn't about game age, but the medium of the game itself. Because if you bought Playstation All-Stars on disk, the medium of the game is expected to warp, scratch, and so on. Digital distribution has no such limitations, supposedly.
I'm sorry, I don't really understand what copyright law has to do with it? As for the price dropping, that is something I admittedly can't get my head around. Steam works the exact same way as shops do, you might get a discount on a preorder, the game sells for the full price for a while, then there's a sale where it drops a little and then goes back up to full price, years later the game might halve in price, it might not (depending on demand). I imagine the reason that it doesn't work that way on the console stores is because they don't want to annoy the brick and mortar shops that sell their hardware, but even then I don't really get it as, last I checked, Game (and presumably others) sell PSN content as voucher codes in their stores, so they can still profit from it (even if it is a little bit ridiculous to go through a middleman like that).
And yeah, digital distribution is immune to ageing, I can play 1993's Syndicate right now if I want but even if I could find my disk copy of it, I don't have the required hardware for it.
You're forgetting about online sales, they're still huge for physical console games even if high street stores are going away.
I actually read in the "paper" (if you can call the Daily Mail that) today that... You know what, never mind, that's a less credible source than
Wikipedia a random drunk guy in a pub.
However, when high street stores do go away and you're left with a choice between ordering games online or buying and downloading them, the biggest advantage that physical copies have disappears; namely the instantaneous...ness of being able to walk to the shops, buy a game, come home and play it. Even with a ~5-6Mb connection I can download approximately 1GB in about 15-20 minutes, the average sized game (let's say, 8GB) takes about 6-8 hours to download. Ordering from Amazon, if you don't want to pay for delivery, can take over three days. If you do pay, you might get it the next day (then again, you might not). So, I think if most people were given the choice, digital distribution would take over very quickly indeed.
I am, of course, ignoring the downsides to digital distribution but I'm still talking in the context of Sony's patent which aims to limit their customers' ability to resell their games (which is the main downside to digital distribution). Digital distribution is, in my opinion, a far less 'evil' seeming method of reaching the same goal (but it's still quite evil).