Flight simulators often have such a high price tag because they are developed by organizations entirely committed to producing such intricate virtual creations. These goods are eventually sold at such a premium price because the real customer base is so small, even though the R&D that goes into making them might easily total hundreds, if not thousands, of hours. So it's like how luxury manufacturers can get away with charging such high prices: they know their wares are highly specialized, so they have to charge a lot to recoup their investment.