Not going to go back an quote things.
The point that the company has to provide two of everything is flawed. If they provide the phone and adapter they can leave the home side on the user. Obviously if they require working from home, they are likely more obligated to provide the environment. Most home based sales people I know have a KVM setup for their laptop at home that they supplied because they like it better than their company laptop alone.
The company can easily handle providing the KVM at the office because they would have it anyway for a desktop.
To another point, of course it is not supposed to be a laptop replacement. It is supposed to be a replacement for a docked laptop (docked being loosed used in this case to refer to one sitting on a desk for long periods or actually docked).
To @Dashrender's point of the documents being with them, well duh, that has nothing to do with the actual hardware and is a solution that would have to be decided with a desktop or laptop at home anyway.
To @scottalanmiller's point of laptops being more usable. They are only in so much that they have the keyboard and screen included. but you pay the price of carrying around that weight. So more usable is a relative term based on perception and use case. With a device and a KVM at home you only have to carry the device and adapter back and forth, instead of the entire laptop.
@DustinB3403 said something about double everything. Well as I think you see, double is the user's choice. Full system at work, work from device on the road and at home unless they choose to enhance the home experience.
tl;dr: I think this is honestly a solid solution once the mobile OS get fully up to speed. People will adapt.