They aren't. They're premium, for sure, but you'll struggle to find a similarly specced Windows machine beating it by much, if at all (and when I say similarly specced, I don't just mean a shitbox with a big, slow SSD and a ton of budget ram, I mean something with a decent display, good build quality, fast storage and ram, a powerful and efficient CPU, and silent/fanless if comparing to the Air).

I will grant you that Apple has lost their fuckin' minds with ram and storage upgrade pricing, but the machines as a whole are not that expensive relative to the competition.