The production costs play a big role into how big of a pricedrop they can do. You're right that we dont know the production costs, but i think it is a safe bet to say that the Vita is more expencive to produce. Not just because of the more powerful hardware specs itself, but the Vita is also being produced in a smaller scale (at least i cant imagine that the Vita hardware production is at full speed concidering the slow sales worldwide). It is for example very doubtful in my opinion that Nintendo would have done a 10k yen pricedrop if the 3DS production costs were much higher. But since we dont know the exact production costs, this is just speculation indeed, but the production cost is an important thing when pricedrops are concidered.
I see your point about being more agressive, and i agree that this can be a good thing indeed, but it comes down to how much losses they are willing to take. It is a bigger gamble the more losses they have on each unit.
I dont think that it is arrogant at all. In that case you can say that it is arrogant of Nintendo to not match the WiiU Basic Set price compared to the PS3. The difference between those system is also about 1000 yen (the PS3 is 1270 yen cheaper than the WiiU Basic Set to be exact). I dont think that this is arrogant of Nintendo at all. They try to price the systems as low as possible. Dropping the price with another 1000 yen means less income. Its the same of every company, inlcuding Sony with the Vita.
(Not that important, but i just want to say that i dont concider the 3DS XL to be a premium model because it has the exact same features as the 3DS, the only difference is the bigger screens).