I might argue the real productivity gain is coming from the elimination of the commute. Its less strictly comfort of the home office and more the elimination of the need to travel long distances in a car before and after work. You can "show up" early and "stay late" when its a matter of walking in and out of a room in your house, rather than traveling 20 miles on a packed freeway.
Most commutes are under half an hour. Comfort over an 8 hour day will have a far greater impact on productivity than not sitting in a car for 25 minutes before you get to work.
I used to commute that for school and at least I got a lot of reading done. I feel your pain. But I can only do so much reading before losing my mind. Lol
There are still 47 other states. I know I know, it's hard to believe but most of the US is not in Texas California and Florida. Most people's commute is still about 27 minutes.