I get it OP. My place is hybrid but more and more of us are choosing to come in full time and just take advantage of flexible WFH now and then when there's a practical reason.
I work for a global company so remote working and collaboration is nothing new, but exactly because of that we've always known that even if you've been workong effectively with people in another location for years, it still steps up a gear when you visit in person.
We've got all the clever communication and collaboration systems in the world but they don't hold a candle to face to face human interaction. It's all the nuance and instinctive awareness of others that comes with eye contact and body language. Not to mention the social/watercooler chat, the value of seeing who else is talking to whom, seeing which groups are in meetings together, knowing when a good time to interrupt someone is...it's just a whole different world.
I can imagine if you do line work, where you perform a well defined (albeit highly skilled) task in a process, WFH works great. I'm certainly not knocking it for everyone. But when you are part of a team creating new solutions and new processes, when for a significant portion of the time the thing you area working on doesn't exist yet except as a shared idea in people's minds with a lot of grey areas and some documents and diagrams you hope are starting to capture it and you hope everyone reads the same way, being in the same space makes a real difference.
IME, in the type of role I do, the people who say they don't need to be in the office are (usually, not always) the ones who most do, because they are tending to assume their take on a problem, process or challenge is the same as everyone else's. Then of course when they find out they missed something, or when things change around us and our thinking evolves, it's everyone else's fault for not realising they'd missed it and telling them.
Yes, a manager can head that off by pulling them back into more frequent online communication to keep them aligned, but reality is firstly since they don't think they need it they perceive it as micromanaging/lack of trust (which TBF if is) and don't engage, and secondly from a manager's POV someone who needs that level of oversight to WFH effectively is hardly proving the case for WFH!
Obviously that type of personality has always existed, but it's a lot easier both to notice when they are drifting off and nudge them back and for them to pick up more of the context from the team when they are physically together. Working in the office, it's not a significant problem, just part of the team dynamic.
That said, selfishly I'm all for hybrid work continuing because (1) I get some nice quiet commutes on Mondays and Fridays and the good lunch places have less queues, and (2) it's creating a two-tier career structure, where those of us who want to come in are finding each other, enjoying working together and accelerating, and those who prefer a job with more chill but less progression get that WFH. Win-win!