First, a lot of studies have shown the productivity boost for WFH may not be uniform or actually exist. Whether the possible productivity boost is worth the money on office space hasn’t been answered, it is likely more in that gray area than WFH proponents want it to be.
Second, while generic work productivity is about the same level, teaching new skills isn’t. We have data showing educating from home has been worse for students, and that seems to be filtering into the office place. Junior staff aren’t picking up skills fast enough and are probably a major reason why WFH productivity measures are lower than expected. It isn’t because new staff are lazy, just that they have fewer people to ask questions to and don’t ask as many questions in general.
Third, building and maintaining a work network has fallen apart. People don’t know others in an office, which can be a problem in flat company structures where communication is not expected to go through the boss only. So you have people who feel like they are doing productive work, but aren’t talking to others. This can cause a lot of rework that the managers see in slipping deadlines.
That said, the answer seems to be hybrid for these jobs as workers won’t tolerate full time in the office anymore. However, hybrid has been a clusterfuck in a lot of companies because the hybrid model is new and not everyone knows how to manage to it.