Sure, there are always other options. But there's also inertia - switching jobs is stressful and risky. Forcing people back to the office provides a push that

Sure, there are always other options. But there's also inertia - switching jobs is stressful and risky. Forcing people back to the office provides a push that might get people to think, "Y'know what, maybe <competitor> will hire me at L+1, and let me work remotely." The employees who can actually get the L+1 offer are the stronger ones.