My perspective is quite different. Perhaps for more innovative companies this is true that it accelerated the trend, but there are plenty of stuck-in-the-mud companies where COVID-19 forced their hand to move to remote quickly, and they would've never done this without COVID. That's was I saw (outside the FAANG, outside the US) in a traditional industry.
There was a telling survey posted some months back (can't find it unfortunately) "What accelerated digital transformation in your company?" and the answers were management or COVID, the response was overwhelmingly COVID.
Also lots of anecdotal stories from senior IT folks. A pretty common theme is that COVID forced a lot of experiments that were on the maybe someday/probably risky pile and a lot of them turned out better than expected.
Another example would be ties; already in Australia it was becoming common to see professionals wearing business casual rather than suit-plus-tie (especially in summer). A walk around the CBD of Melbourne recently suggested to me that COVID has hit suit-plus-tie very hard, but suit and no tie appears to be going strong.
Major (or a subset of) employers do not like losing centralised control of their employees, but there are a large cohort of employees who wish to see remote or hybrid models of work and, critically, this trend was growing prior to COVID-19. COVID merely accelerated this trend, as it did with a lot of pre-existing social and industrial changes.
> And lastly I'm just not convinced that businesses actually act based solely on hard figures.
Correct. Large, Big-5-hiring, corporations are probably going to be the last companies to move to true hybrid models. They are behemoths that cannot be turned quickly. They have slow bones, vast inertia, and long memories, and will have been optimised for reporting chains that require face-to-face interactions and strong visual signaling. All of this takes time to change.
But I wouldn't expect that this return to all-onsite work will be completed before the pendulum begins to swing back again the other way.