Microsoftie here. I haven't seen any indication for it to be due to employee demand. The vast majority of engineers on my team, and my last N teams, have agreed it was top down from leadership; and even those that preferred open offices agreed that cost cutting and space utilization are likely driving factors.

To contribute to the broader discussion; SOME teams here still have offices, but it's a dying breed. I consider myself very lucky that I found one that did, and it was certainly a factor in my choice.

Also work for MS I have an office, but wouldn't care if we went open. I worked for wall street for a while and was used to it.