But society already values flexibility as well. As a basic example, I was hired in my current job in large part because I have a relatively broad range of skills within my field, rather than being hyper-specialized in one particular thing. Sure, in an abstract world where replacing employees is frictionless and firms are all megacorps with tens of thousands of employees (or more), tremendous specialization would probably be more commonplace. But in our real world, companies value flexible employees who can respond to changing projects, requirements, conditions, etc., because just firing and hiring a new specialist costs times and money, and many companies (startups especially) can't afford having thousands of specialists in every niche they touch upon.

Further, even specialists have to communicate and collaborate with other specialists, and they need to be able to understand each other well enough to do so. If you wanted to build robotics to pick tomatoes automatically, for instance, it would be ridiculous to hire one tomato farmer and one roboticist who know nothing about each other's respective specializations. If neither has any flexibility or breadth of knowledge, it will be very difficult for them to communicate and collaborate to get the project working.