> I think that in theory people prefer to have one device , but in practice people are quite happy to have a house with lots of computers in it, after all space isn't a premium and it's nice to always have something near to hand.

This isn't about the number of devices people have. Or in a way it is, because having instant access to your data and state of computation "everywhere" makes having more cheap devices floating around even more attractive. Currently every extra device is a device that might hold data that is not accessible everywhere else, and that might result in data loss, and that need to be "managed" if only in the sense of knowing what you can do which things with or which one has those embarrassing photos and hence shouldn't be lent to grandma.

If they are mostly dumb shells (I'll grant you that having a $25 of computation capability or so built in as "backup" might be useful) and they are just appliances or furniture.

> Regards Local vs Cloud storage, there is no reason that this couldn't be transparent. For example , if you go somewhere and login to a public terminal it could detect that your phone is close by and offer you the option to transfer the state (if it is more up to date than the cloud copy) from the phone to the terminal via wifi.

Latency and bandwidth are killers here, and latency in particular is subject to nasty physical limitations. Yes, it can be more transparent. But network bandwidth and latency are both increasing very slowly. My mobile internet is still only about 1.5Mbps. My home broadband is 8Mbps. If I'm lucky I can upgrade to 66Mbps down next month. My wireless is 300Mbps. My wired network is 1Gbps. I have SSD's at work that easily does 5Gbps, and my home laptop's SSD can do at least 2Gbps. I'd turn it upside down: For personal usage, cloud storage, apart as for backup and sharing with others, is a workaround for the deficiencies that currently force us to use a variety of devices. It becomes less relevant as functionality converges and shortens that gap for everything but "overflow" as storage becomes cheap enough and easy enough that having it elsewhere becomes pointless other than as a backup.

> I wouldn't agree that a requiring a headset would be "besides the point", I think being able to instantly grab your phone and stick it to your ear when you get an important call through is an important use case (after all it is a phone) and one that more than justifies the small extra expense of having a cheap CPU etc inside a laptop case.

And how would it being a computer stop you from doing that?

> For example laptop docking stations have been around for a while and allow you to turn your laptop into essentially a desktop PC, negating the need for a desktop PC. However I don't know anybody who actually uses one very often in the real world. It's simply too cheap to just buy an extra PC and use Dropbox + IMAP Email to handle most of the important "state" for you. An ex boss of mine bought one, but replaced it with a separate desktop about a month later for example.

They are frequently used in businesses. But today they are less relevant because the trend is instead to buy "desktop replacement" notebooks. Desktop sales are stagnating to dropping. There will be more smart phones sold this years than PC's in total, and desktops will be a dropping proportion of that minority market. People opt for laptops instead of desktops, not in addition to them, because they are now powerful "enough" and the mobility, even if it's only sufficient to move it between rooms, is valuable.