Personal productivity isn't the same as organizational productivity. This is one of the key things at the heart of the WFH discussion. It's entirely possible that you personally wrote more lines of code, but the team still fell behind in products shipped. This could be due to many different factors. One easily identifiable one is that while good employees might be more productive WFH, poor performers are even more poor when WFH, and it becomes much more difficult to actively manage/coach/mentor poor performers when they are remote.

There's many more metrics too, like attrition, or poor onboarding experience for new hires, or inability to coordinate across teams (sure you're producing more personal output, but is it the right output?)

Organizations are more than individuals working in isolation. They're coordinated masses of people that have to work together, and what is best for one person's personal productivity may not be best for the organization's overall productivity.

Communication is great for organizations, but I don't understand what you are getting in person that you don't get over zoom talking about whatever you need to talk about. It's not like the entire org is talking to eachother at once in person. At best you talk to like a handful of people a day, probably a good amount of that talk has nothing to do with work. Meanwhile with zoom I've been having so many more directed meetings with key people. Like before, we would sit in this in person meeting and say something like "it would be nice to get Steve's input on this, if he were here in this meeting" and now with zoom we can actually get steve in the meeting. We meet with people from around the world who might have relevant input.

If your issue with wfh is team isolation, just have more meetings and get better at communicating. The issue is not the venue, its the event.

How you know it was not anecdotical due to switching workspaces and it is not regressing to normal?