[Arm-netbook] why are notebook devices not usb?

[Christopher Havel]

Money. It's cheaper to do it that way... touchpads are generally PS/2,
keyboards may or may not be USB (probably also PS/2, actually) -- but the
doozy with them is that the controller chip is on the mainboard to
eliminate yet another PCB that isn't really necessary anyways. I believe
cameras generally ARE USB, but not with any connector you'd find familiar.
Sound is generally integrated into the chipset, and emulates a PCI or USB
device. Sometimes there are external codec chips... it's not common except
on systems with chipsets so awful that sound just isn't included. Thin
clients, for example.

There's also the form factor to consider -- to an extent, there are no
standards for laptop gadgetry because there's no way to do that. Different
laptop sizes and shapes require differently-sized and -shaped crap inside.