Sure, for a few more bucks you can make more powerful systems, but then the competition snaps in. For a more powerful system you'll soon reach price regions where Atom et al are home already. Indeed it is possible to sell stuff there, too. But the whole key is that with the 512x family you could offer small cheap computers which in that kind are pretty rare yet. Nothing to do too seroius computing on, but for fun, for niche, for lowest price. That's the whole point.