It does feel like a shortsighted strategy, for the exact reasons you claim - the high performers can flee and you're stuck with those who can't jump. But, just because it's a bad strategy doesn't mean it isn't also the one being followed. According to at least one study[1], there is a considerable chunk of employers that hope that RTO will lead to voluntary turnover.

[1] https://www.bamboohr.com/resources/data-at-work/data-stories...