The general reasoning given by a lot of these companies is that WFH did not work. Same companies were telling is how well it worked and they had the numbers to back it up. I think they are looking for scapegoats for some cost cutting. Officially force people back and hopefully some will quit. In practice, many will continue to operate as before.
I work for a company that made a big deal about how well it worked. The CEO and chief people officer both made a lot of public statements about it, during and just after covid. They did this claiming they had the numbers to back it up and said numbers but they basically made them up. It was PR and they were using it to aid recruiting into what was and is a company that young people avoided. What numbers they did have…
They go remote, but don't change a lot of other things or attempt to mitigate the downsides (there are downsides, everything is a trade off) and then claim its a failure when they need a stealth layoff.
Also IBM has a long history of "Resource Actions" so this type of thing is not all unexpected from them.