I expect this topic to be met with a bit of negativity, but please hear me out!
I work in a small office (circa 50 people) and we have largely been working remotely during Covid. There has been a return to a flexible working routine by many, whereby they would come in for as many days as they wanted. However, we've noticed that some people have either not returned at all, or only come into the office very occasionally.
I'm not in upper management, nor am I someone that's focused on the profitability of the company, but can see the negative impacts it's having on the company as a whole. There is much less engagement between people (which we rely on), there is a lower quality of output (due to lower supervision / access to help) and most importantly, very little social interaction and comradery.
I don't think a lot of people see the benefits from physically being in the office. Sure, there are occupations where remote working full time makes complete sense, but there are other roles where it does not. You have younger members of staff that need constant help (it's a lot more difficult to make a call to a manager asking a "basic" question than it is to ask your colleague sitting next to you), you have more experienced staff that learn new things or save time on their current task just from random conversations when getting a coffee and then of course there's the social aspects where you actually feel a part of the company and not some mindless and faceless job. I think the social parts are the most important and what makes where you work enjoyable and not something you dread doing day-in day-out.
I'm not in the position of actually hiring or managing these staff, but I don't like how things are panning out. I'm very much in favour of flexible working and regularly take advantage of working from home, so I'm not one of these people who want staff to be in 24/7. I also don't like the idea of people being forced to come into the office. This would only breed resentment and people will look elsewhere for work where they offer more flexibility.
So in reality people need to want to come into the office, particularly those who don't see the advantages I listed above. So how do you encourage people to return, even only on a limited basis? I'm thinking encouragement, things that would make you say "oh I don't mind going into the office today because of X, Y & Z". Is it maybe free lunches? Flexible start and finish times? Social events like beers after work? Would anything make you come back? I'd be interested to hear what you think.