These large corporations aren't making decisions without the data. In fact, they tried this experiment for years and the results are in: full-remote is less productive.
That's not to say specific people shouldn't be remote. There's probably an optimal distribution that allows some slack for these ICs who are bad at being in the office.
Now they want us back in a few days a month, which isn't too bad I guess. But it really has nothing to do with productivity.
We do less work when we commute, socialise more, don't accept early or late meetings, etc. Our teams are distributed across India, the UK, the EU and the US. Most of our actual work takes place on webex calls, even pre pandemic.
Now, it may be that the leadership value intangible things like culture and have decided that those are also important things. But at least for our company, productivity is not the reason they want us back sometimes.
Personally I find myself thinking “I need to discuss this thing with this person, but I don’t feel like booking in a meeting and having a video call, I’ll just wait until we see each other in the office some time”