It's to weed out the types of ego-driven employees who like to threaten lawsuits and publicly complain about the companies they work for. They'll lose some productive individuals.. but companies need their full teams to build success together, not just a series of individuals working for their own personal success at the expense of the team.

If any individual could complete the product on their own, then the company itself would be pointless. Individual success is not mutually exclusive to team success, but the people who do not work well on teams are unlikely to return to office (or tolerate similar actions). Companies know this, and they've learned they can't find toxic employees by looking at individual success alone.

There's other ways to find this dysfunction, but looking at team metrics instead of individual means you have to cut an entire team to try and force out maybe a few employees who actively hate the company. RTO is a unique opportunity to try a different, and perhaps more targeted approach. There will still be an some great team members lost for purely physical reasons, but perhaps fewer than firing entire teams.