my experience is that there is FAAAAR more time theft in the office. coffee, extended breaks, walks, catching up, meetings running long to shoot the shit, " oh hey, did you see this happen last week", those quick "what do you think about... that turns into 30m convos. I clocked over 2 hours of wasted time every day for the average person for the 4 teams I am able to observe from where I sit. all expectations were met, and on time and on quality with this 20% time wasting.
wfh has freed up 1.5 to 2h a day for me because people don't walk up to my desk a literal 6 times a day to go get coffee or see what's up. also the volume of "can I run something past you" had plummeted to only 10% of what it use to be. that use to happen once or twice daily, and now happens like once a week. if people don't see me sitting there, they don't ask me how to do their job. it's amazing.
not to mention I can now walk on a treadmill while at my desk, save time commuting, save money on dry-cleaning and gas, and I can be productive with my life during all those meetings you are forced to attend but don't involve you in any way. wireless headsets with the camera off is great. I can talk when needed, mute myself for 50 of the 60 minutes, and do a mindless task like vacuum, dust, dishes, fold laundry, etc, while listening to people debate pointless shit.