I think if people were just as productive at home, then more companies would already do it. What company wouldn't want to save on office space? But realistically, how many people working from home even have things like safe office furniture. A couple of weeks working on a laptop on the sofa might not be a problem, but they'd have to pay to kit out everyone's home office if they wanted them to work from home permanently, or risk getting sued for injuries.
Also let's be honest, if you can do it from home then it's not a proper job, is it?