Earlier quoted context omitted.
Trust issues. While 80% of employees could be more productive remote, 18% could have serious issues with productivity and 2% might actually turn nefarious while remote (steal company IPR or something like that). Or I would imagine thats what the fear is.
People underestimate how unproductive (or nefarious) one can be in office.
I think we've all had days where we've gotten to the office and had a problem we're working on that doesn't get solved that day. It is actually really taxing and feels really bad to not accomplish anything, as if you've wasted the day.
I've found that the ability to more strictly control distractions at home--not needing to deal with the pressure to chat with co-workers and eat lunch together, for example--has led to far, far fewer days of no-solution. At the same time, it becomes even hard to "give up" on that day's productivity and clock out, since there's no real leaving the office.