Simply having a patch written is insufficient, as most scenarios that would take Steam's servers offline for good would also involve either creditors or new management, both of which would likely block the release of such a patch in order to preserve some of the value left in the company. That's why it's essential not only that a patch be written, but that it be placed in escrow with a third party to be released under the condition that Steam's servers are no longer available; this ensures that no one involved with Steam now or at some point in the future can block the release of the patch.

Why does this all have to hinge entirely ALL on Valve if Steam goes out of business? It should either be Valve OR the game company that made the game taking care of this matter. OR, whoever is the current owner of the game's IP.
If Steam goes down in flames and say the developers who let their game be sold on Steam are still in business, they should take it upon themselves to support Steam customers -- whether patching the game with an EXE so it will not Steam, sending them a retail-boxed copy of the game that has no Steam around it; etc etc.
Same goes for publishers, too. If Steam goes down in flames and say EA's still in business, EA should provide Steam versions owners of whatever game some way to still play their game -- whether sending them a retail-boxed copy of the game (see Prey when some other DL service went down, all members of that service got a boxed copy shipped to them); allowing them to use the "Game Key" from Steam to say download a copy of the same game off their EA Download service; providing a new EXE file or new patch to remove the Steam protection from around the game; or whatever the case may be.
If the dev's are out of business for an old Steam game you own and say Steam's about to go under, yeah -- Valve really should release a patch to run that game without needing Steam DRM.

The thing is there's absolutely no motivation for the developer, publisher, etc to release a patch for their games sold on Steam, and moreover it would probably actually be illegal for them to do so in many jurisdictions, whether due to their contract with Steam or due to laws like the DMCA.

One way is if releasing a patch breaking Steam's DRM would violate the contract the developer/publisher had with Steam. This wouldn't technically be illegal in a criminal sense, but would be a tort that whoever controlled the remains of Steam could sue over. With regards to the DMCA, under this law distributing tools to circumvent copy protection of digital works is a federal felony. Even if the person/company breaking the copy protection owned the copyright of the work the fact that the specific copy and copy protection was licensed to and distributed by a third party could probably land the developer/publisher in hot water if they wrote and released a patch. It would actually be a rather interesting case to watch play out, in a mind-numbingly stupid kind of way.
Now, it's unlikely that either of these situations would actually play out, but rather that the lawyers for the developer or publisher would quickly put the kibosh on releasing a patch unless whoever controlled the remains of Steam explicitly gave them permission to do so.

I can't tell if you know what you're talking about or if you're just making stuff up.

You know, of all the crap that whiners whine about concerning Steam, if we didn't have Steam the pc gaming field would right now be covered in Starforce and Securom.
It's kinda funny when people whine; the other option is never better.

I prefer Starforce and Securom to Steam DRM.

You're kidding.
Right?

No. Steam is much more invasive. And it can have the same limitations on installs, et.c., that publishers may elect to use in the other systems.

Also starforce & securom are easier to crack that an egg.

Wow. You guys need to actually read what they do before making such baseless idiotic remarks.
Esp. concerning Starforce.

Well, you should do the same, and I suggest you start here: [url=]http://www.tweakguides.com/Piracy_9.html[/url]

Unfortunately, that article is as full of misinformation and omissions as it claims everyone who's ever criticized any form of DRM is.

The simple fact is, Steam has never slowed down my system, caused BSODs, killed drives, destroyed pcs, like Starforce did, no matter what some fanboy read on a blog.
To be honest, and I AM going this route, if you are trying to tell me Steam is worse then Starforce, I think it then boils down to you not wanting to pay for the game to begin with.
Esp. when you start talking about cracks.
I used games with Starforce for a few years. Your a fool if you think Steam is worse, as bad, or even slightly bad compared to it.
If you actually used Starforce you'd know how bad it is. I think the issue here is having to use Steam for online gaming versus the 5 finger discount for starforce games.