Sorry, but tell me how someone other than the ROM modders would preserve something like a cartridge based game of which the source code was lost.
What does source code have to do with anything? Do you think Nintendo needs source code for their Virtual Console games? No, they just throw the ROM up and call it a day, which is why so few games get changes, and when a game does get a change, it's very small (they are "hacking" the ROM). And XBLA versions of classics are recreated from scratch, no source code used at all (which is why they are often not 100% accurate, like Frogger having different music).
(Quoted the above two posts together because Dreamwriter was responding to Des0lar.)
I believe it is important to have
both the source code and ROM images archived. The developer and/or publisher should maintain copies of the programmers' source code to aid in the creation of future conversions and emulations, but the resulting ROM images should also be preserved. In years past, some developers have discarded their source code, but I believe (and hope) that modern developers are much more careful to retain the source code.
One reason why developers should archive their source code is if you want to do a conversion or a port from one system to another. Sometimes the port is being done by a different entity than the original author, and it's easier to understand what's going on and what the programmer(s) intended if this is written in a high-level language (or at least assembler with comments). If the source code is unavailable, then the task becomes much more challenging--sometimes incredibly difficult or nearly impossible.
Without the source code, programmers who ever want to offer modernized versions of old games have to do at least one of the following:
1. Emulate the original game's target hardware, and run a copy of the ROM image on that emulator.
2. Disassemble the game and analyze the program to the best of your ability.
3. Rewrite the game from scratch, and try your best to replicate the level design, movement routines, patterns, physics, AI, etc. from your knowledge of previously playing the game.
#1 is obviously what you do for something like Virtual Console or some classic game compilations, where the intent is to replicate the original game as closely as possible with no alterations. (BTW, Dreamwriter, there have been some emulations on XBLA/PSN as well.) #2 is painstaking, but it has been done before, and a skilled programmer can sometimes get really good results. #3 is usually done when #1 and #2 are not viable options. For "enhanced" ports or emulations, they may use multiple approaches.
This is why people are lamenting the loss of the source code for Panzer Dragoon Saga--it might never exist in an "enhanced" form that's noticeably improved beyond the technical level of the original Saturn game. This is also why the developer that ported R-Type III to Game Boy Advance had such a difficult time doing the conversion.
Having the ROM images at least ensures that the games would at least still survive in some form for future generations, but developers retaining their own source code could also provide a great benefit to future generations of game development.
No university or library is going to have the expertise, time, or budget to circumvent the DRM on the original media or code a near-perfect emulator for old hardware.
Pirates do all of this for free in their own time, and this facilitates archiving and preservation. They don't do it for those reasons but it's a beneficial side-effect of piracy. That's the whole point of the OP.
Yes, that's true. I don't think very many people are advocating piracy (I'm certainly not), but a few extreme cases (such as the one I mentioned earlier) the work already done by pirates can be reappropriated by the original IP owner for a good purpose. Still, I would prefer that companies do their best to archive their own ROM images, since occasionally the pirated copies may have slight alterations that are not easily detectable. Some of these modifications could have a detrimental effect on the purity of the game, such as altered in-game text or bugs that crash the game.