But people are definitely less productive working from home

How so? I personally think it's a very personal matter. I am far more productive working from home, mostly because I don't get distracted by colleagues who spend hours bantering only to then stay in the company until later to compensate for the banter - I'd rather get my work done so I can end my day on time and go home do the fun stuff. But I do have colleagues who say they get distracted easily when working at home and they'd rather work at the office.

Overall though, my company used to be very against working from home, but after the period of mandatory work from home, management admitted overall productivity had increased. They still insist people should come to the office every now and then to maintain the "friendly" environment the company is supposed to have, though, which is fair I guess.