Not everything scale that simply.

Let's go for one very simple issue: Chips. Chips can only be made so small for physics reason. We're currently making chips and motherboard so small we can't make them smaller and still have them function reliably. We're talking nano meter wide circuitry. You can almost count the wideness in terms of molecule. A single grain of dust can already cause malfunction in these kind of things.

Nanomachines (son) are still really far away from being an effective solution. And that's not talking about batteries autonomy on these things.