Same. I have fond memories of working in a small team (~8 engineers) in a single room around 2010-ish. We'd often just walk to each other's desks, read the body language and ask each other "what are you working on?" and just engage in these unscripted, natural discussions that may have resulted in a pair programming session, or a cigarette outside accompanied by some good old-fashioned complaining about management.

Don't get me wrong, I think working remotely and home office are great. But something was undeniably lost, at least for me.

Walking to someone else workstation is a different thing from the so called "water cooler talk". When you go to or simply turn to the nearby team member (or even far away) you initiate a conversation one way, so you judge when a person is not busy and ask him/her. And then discussion happens. This is not unlike a call to that same person (you can ping him in chat to clarify if he is busy) and in general is a close enough substitute for office, at least remembering that for that small quality of life improvement every person mush pay with full 30 awake days per years of wasted time for commute.

But the original proposition by the RTO managers is different. They posit that such spontaneous talks happen in a place different from any workers workstation, e.g. watercooler or kitchen etc. That is a two way conversation which to happen much check the following - both (or more) persons mush happen to go to the same place at the same time, and they both must have a topic to talk about in that particular moment. And those linkedin propagandists claim that a lot of such talks are supposedly highly technical about the project itself. Which is honestly never happens in my limited anecdotal experience.

I think the biggest change with online communication is moving these random encounters into peering into what other teams are doing, or what they're discussing.

For instance we had someone from a completely unrelated team bump into a project thread discussion our firewall rules, and coming up with the proposed changes he was working on and wanting to brainstorm something that could work beyond his team.

You'd need an incredible level of luck to bump into that precise discussion at a water cooler, and it would require a super broad call to get people to gather on that subject the "normal" way. But having most communication in Slack, indexed and accessible cross-team gives incredible opportunities for these kind of interactions that would be just impossible on the previous office culture.