These researchers found that if you work from home you will be less efficient and productive than people who from their office. Can we say the same about freelance workers? Do you think that if workers are given the chance to "own" a task like freelancers they'll be more productive because it is just like being self-employed where you treat it as your business and not with the mindset of another man's business?
I do not share the same opinions of these researchers. Employees do not become less productive just cause they work from home. Admittedly, there would be some few people who might actually become less productive due to working from home as well with other reasons but I think majority of people who work from home tend to get the job done.
There are employees who work much better and are more productive with little to no supervision. Without your supervisor being physically present, breathing down your neck, watching your every move and making sure things are done by the book, an employee could learn to be innovative and more effective than others physically going into the office.
I think it mostly depends on the employee and the approach to work. An unproductive employee would remain unproductive working from either the home or the office.