But they can't just transfer coding from one console to the next...the results are completely different for a PC, Playstation 3, or Xbox 360 for the exact same equation. They would still need to test extensively for the 360 and PS3.
The 360 has bugs, that PC users don't have at all(no user content), and the PS3 is having huge issues because of the way they use RAM. These are just a few of the things that make patches using the same code for multiple platforms impossible. Not to mention the coding language is different.
It'd be like saying a program proved on Windows will work exactly the same on the Mac.
Skyrim had some issues with the PS3 in the first place, so let's remove that out of the equation because the consoles architecture dosnt agree with Skyrim. But as everybody knows, the Xbox is much easier to port to, and if they bothered to find ways to massively fix glitches in the game instead of just pumping out content (lol hearthfire dlc), or just put more resources into that development to make the base game more enjoyable itself (for the people who are going to come in saying the dlc team is different than the glitch team), they would find out how to patch them for the PC, even releasing smaller patches to see how it agrees with the game, and then internally test for the Xbox, which would be easier to fix than anything PS3 related assumably since the base game didnt even work right. But instead they barely release patches and when they do they end up breaking more things instead (how did this get through internal testing??) and it ends up being a waste of their time, and costs them MORE money.
There are a lot of variables to account for when programming...misplacing a character, putting in efficient coding, a lot of things can go wrong even for simple programs. With games like Skyrim that use thousands upon thousands of lines of code, it can be almost impossible to find out where you went wrong; which is why it takes so long. Now imagine all you have to go on is "the game crashes out on x", that could be any number of things wrong from conflicting lines of scripting to any other number of errors.
They probably do internally test the code before release, but it costs thousands just to release a patch onto Xbox Live.