For the same reasons fortune 500s will spec the same for their office workers. Labor is expensive compared to hardware. It is often cheaper to spend a little bit more on hardware to avoid supporting multiple configuration, exceptions, more frequent updates, support tickets from power users, etc

If you pinch pennies buying a spec that exactly meets today’s needs, and next year MS Teams releases a new update that requires more resources, you don’t want to buy a whole building full of new computers.