It's not that complicated. If you fire all the 35-60 year olds you get sued. However, if you tell everyone ages 20-60 that they have to move, you will get a disproportionate number of people 35-60 refusing to move - and it's legal. They have kids in school, they are married, they have a house, etc. They are also making more money. Telling teams to RTO especially to move to do so is one of the simplest cost saving tricks any tech company has.