I think that's exactly right and I've even heard CIOs use the term "forced experiment." A lot of things companies have done which have turned out more OK than they necessarily expected were probably on some "Interesting idea. Maybe we should try this out in some indefinite future" list.
Playing a little bit the devil's advocate here:
Risk aversion and general tendency to apply gradual changes.
Would you bet your company to run an experiment almost no one else is trying? Perhaps letting your workers work from home works perhaps you'll miss all deadlines and generate all kinds of drama.
An external factors kicked in and everyone was in the same experiment. Things were messy but not completely unmanageable. Some were even surprised things kept working as well as they did.
Now, the big question is: will this take a toll on people? Will companies that choose to continue with this work style be put in disadvantage as other companies switch back to on-prem?