Because every Apple fan and gadget fashionista will automatically buy it anyway. As long as it's sleek and expensive enough to brag about on the internet.
Even if Mr Jobs pulls a solar-powered calculator (iAddsUP) out of his shirt pocket and announces it goes on sale - tomorrow! - for a mere $699 for the 8-digit screened version and $799 for the 10-digit screened model, it'll be a smash.