The problem is these materials are typically composite materials that have not just the 'raw' carbon fiber bits, but also various resins and other binding materials. We actually have the same problem of not being able to recycle fiberglass already. The early wind turbines which are now at end of life are actually just being buried (landfilled) rather than recycled (https://www.bbc.com/news/business-51325101). There is potential to overcome this (https://www.compositesworld.com/blog/post/perhaps-were-getti...), and techniques for recycling other composite materials like SMC (https://www.proboat.com/2016/09/recycling-dead-boats/) could be adopted perhaps. But in the end it'll come down to the economics of it, and we really need to move to a world where repair and reuse is easier, rather than expecting a black box recycling process to solve our problems.