Agreed. Plenty of similar companies are making the same type of mandate despite having no tax incentives.
Quite clearly, execs at these companies believe they get stronger productivity from people working at the office, and this would outweigh any attrition from people leaving from RTO mandates. I don't care how many people scream about how that's false -- what matters is that the people making these decisions _do_ believe it.
Maybe the tax incentives are a nice bonus, but there's no way it's the entire picture.