I think you are working from a false premise. Modern astronauts are many things, monkeys in a can is not one of them. They have many roles and skills ranging

I think you are working from a false premise. Modern astronauts are many things, monkeys in a can is not one of them. They have many roles and skills ranging form engineering to teaching and many things in between. They perform engineering and procedural review. Carry out public outreach that inspires scientists and engineers of the future. Manage operations during launch and in space operations. and are involved in most parts of approval of new equipment they will be using. Yes they have a PR role, but getting photographed on the top of a rocket is a very small part of that.