I'm surprised they went with a custom AMD part. Seems expensive for what is likely to be a low volume product. Why not just do a laptop in a handheld form factor.
I don't think you come at the Nintendo Switch expecting low volume. Whether another company can be successful at it is a good question, but if you build expecting low volume, that's what you're going to get.
Nintendo has some rabid fans as well as selling mostly exclusives. Valve's market mostly already own gaming PC's and won't buy a handheld. It's just too expensive for the few time's you want to play games and aren't at home. For most people.
