There’s no doubt that Sony spoiled us when it made the PlayStation 2 backwards compatible with original PlayStation games. The convenience of being able to immediately tap into a giant library at launch was a hit with a lot of people. Though there was some legacy support to be found in every console over the course of the last generation, the PlayStation 3, Xbox 360 and Wii all had issues at some point; Sony and Nintendo eventually stopped including the required hardware in their consoles, and Microsoft relied on spotty software emulation that was abandoned by its developers well before it was “complete.” Still, backwards compatibility felt like the rule, rather than the exception, for a while.
Consequently, people were understandably surprised and disappointed that neither the PlayStation 4 nor Xbox One would ship with legacy support in tow, probably due to a lack of understanding that a shift in hardware architecture, which in turn affects how game code is interpreted by the console, is the main culprit. There are a lot of advantages to switching to a familiar, PC-like x86 CPU, especially for developers, but simple implementation of backwards compatibility is not one of them. This isn’t a total roadblock, however, as evidenced by Digital Foundry’s recent report that unveiled the existence of a PlayStation and PlayStation 2 software emulator currently in development for PlayStation 4.
There’s been a lot of excitement surrounding this bit of news, and if it turns out to be true, the first thing people want to know is if PlayStation 4 will support physical games, or, will Sony intentionally block discs and force people to pay for digital copies? I don't think Sony is in a position to do the latter.
In light of Microsoft's early mishandling of marketing the Xbox One, Sony has a positive, pro-consumer image to uphold, and if it doesn’t prevent the use of old PlayStation media, it would earn no small amount of additional goodwill by simply not acting greedy. There's no technical reason why discs wouldn't work, so strategically forcing customer's hands by blocking them would be a serious misstep.
Digital distribution and monetization of assets is a trend that’s cropped up in the last console generation, and it’s had a major effect on the way companies like Sony manage their portfolios. It’s a business, after all, and its required of them to make a profit. However, that doesn’t require imposing unfair restrictions and limiting access to features that customers will reluctantly pay a ransom for; it can also come from earning new customers by simply giving them what they want.
Sony's done it in the past, even at its own expense; it manufactured every PlayStation 3 launch model with PlayStation 2 hardware inside. While technically perfect, this was killing Sony as each system it sold came at a $200-300 loss. It wasn’t until the end of 2010 that Sony was able to manufacture consoles at near parity with PlayStation 3’s price tag.
Removing backwards compatibility was a major factor, and it upset a lot of people, but it wasn't because Sony was trying to reduce value. Rather, it was part of saving the PlayStation business. Thankfully, the original PlayStation library was safe since the PlayStation 3 was powerful enough to emulate it though software alone, as the PlayStation 4 is for the PlayStation 2. Plus, Sony allowed people to use their own discs. Why should that change now?
Sony may not have brought the UMD Passport Program out of Japan for the PlayStation Vita, which was designed to ease the transition away from UMD drives, but according to an interview with Wired, Shuhei Yoshida noted that prices on PSN in the west were adjusted to account for this gap in service. In fact, outside of games published by non-participating publishers, there isn't a lot of moaning about the price of digital PSP games in the west because most are a lot cheaper than their physical counterpart.
Sony allowed people to use their own discs. Why should that change now?
If Sony is indeed working on the rumored emulators for PlayStation 4, it’s going to be a long time until they're in the hands of customers. The smart thing for Sony to do would be to follow the PlayStation-PSOne Classics model by giving customers the choice to use the provided technology how they wish, and I believe Sony's got enough smart people who recognize the importance of doing so. Digital games are in a lot of ways attractive, even to people who own physical copies of their favorite old games, but not everyone wants to (or can afford to) repurchase a game for the sake of convenience. If Sony wants happy customers, it has to leave that decision up to those customers when the time comes. Otherwise, it may unnecessarily burn bridges that are worth preserving in the long run.