I meant it as 5 plus years they've been working with the current hardware. Over 5 years. They know the ins and outs and the tricks and techniques now.
There are tons of ways to implement stuff. Some ways are much better than others. I'm sure they've gotten better at this now, but I don't think we can just say that they simply "know" every optimization trick there is. They surely know more than in Oblivion, obviously, but we can't just say they know everything. That's just speculation. That Skyrim still got loading screens can make one wonder how well optimized the engine really is. We simply don't know and we need more info on it.
This is one of the reasons why I would think it would be nice with full "technology" interview. About the engine, its features, improvements, technical stuff etc. Most game developers I know have this. Kind of expecting it for Skyrim, especially now that they got a new engine.
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OT: 30-60 seconds loading times? Seriously? That sounds insane. Seriously. If my comp had so long loading times for Oblivion I would have quit the game long ago.