Calling all the engineers

I was going to write another post in the "english-is-fun" category, but decided we need to discuss more computer science around these here parts.So, I have Very Important Question for all the engineers out there:If memory is so cheap and advancing so quickly, why can one not buy one of those cute MacBook Airs with half a terabyte of solid state disk? What's up with this 64G stuff? That's barely a few days of photographs from my fancy camera....