An entire generation of web designers have bootstrapped themselves into the profession without the need for a n actual client or project, or anyone else’s involvement or permission. That experimentation is how we learn.
But for a service designer, not only is such an arrangement less than ideal; it’s completely unworkable. Clients and the interactions they embody are the medium of a service. Designing without a client is like cooking without food. You simply can’t credibly explore beyond the line of visibility without access; or prototype without the cooperation of the people and systems involved. Speculative service design requires buy-in from the client (or at least acquiescence) on a scale that dwarfs the first-order disciplines.
Cobbling together that access is one of the core responsibilities of design schools.
This is very true and quite a challenge.