I think in slightly simpler times. Value isn't only about function, its about form and also timely availability. Some devices are required at a certain point in time and although an application could replace them it most certainly will not. For instance the simple mirror, you can use an app on a camera enabled tablet (which might even allow some cool things like virtually trying different looks etc) but the simplicity of our current solution is very comfortable.

The same argument can be applied to the scale example pg gives. Sometimes when you are dripping wet, in the privacy of your bathroom, a scale is just perfect. That doesn't mean your scale will never talk to an app that let's you track your weigh-ins, it just means a scale is a dedicated device that people will likely want to keep for the foreseeable future.

But pg is dead-on on many items, as are you. There will be, as has been, a migration of specialized devices to software solutions.

Where the line will be drawn (due to consumer preference i.e. value creation) is up for debate though!