The margins on netbooks are currently so small that they're essentially a commodity, and apple has never been a commodity company.

Netbooks are clearly popular, so it seems unlikely that apple simply isn't interested in the market. The question is "can apple create a netbook that's differeniated enough from the rest of the pack that they can get the margins they want on it." The fact that one doesn't seem to be in development yet suggests the answer is 'no', but they may just be focusing their resources elsewhere.