Nevertheless, this is irrelevant to Skyrim. Simply set Steam to offline mode and you never have to worry about not being able to play due to Steam offline issues or patches, ever.
I'm honestly not sure why you have so many problems. What region are you in? I'm North-East US and over the past 4 years (since Orange Box was released) I've been almost 100% Steam for all my purchases. I've never a single time gotten that "unavailable" error. I'm not saying it doesn't happen, I'm sure their servers go down as all servers do at some point, it just seems odd that some people seem to see it happen so often when it's never happened to some of us.
I have 183 Steam games, I've left it running virtually 24/7 for the past four years, and I've never had a game unavailable or experienced any performance issues from it. About the only problem I've ever had with it was when I was doing something else like watching streaming videos online and it start downloading game updates in the background that slowed down my connection, which I then had to click "pause" on to get it to stop until I was done with the other stuff I was doing.
I've also never had offline mode not work like has happened to some people. I live in the woods and my cable goes out a couple times a month. Steam has never failed to start in offline mode and let me access my non-online games.
I consider it a huge negative when games are not Steam games now. I vastly prefer when they are fully Steamworks games in fact so I know the integration will be tight and there will be no worrying about different versions and such. I completely understand why people with slow or metered internet connections can be frustrated by this, but online distribution is the way things are going (not just games) and I don't see that changing.
The extremely unobtrusive and minimal Steam DRM implemented with Skyrim (online activation only, then you only need to ever connect to Steam again for patching) to be difficult to find fault with. How would it be any different if you were connecting to proprietary Bethesda servers for those functions anyway? Steam probably has a much greater availability rate than any individual game company would manage running their own servers anyway.

Only real purpose to requiring Steam is to prevent people from loaning / trading / reselling their copy. (It doesn't work as DRM, the pirates already beat that. Like they do with any system. Disc check would be more than enough to stop the "casual" pirates. The high-end ones won't be stopped by anything.)
