To be clear - I am not so prehistoric as to deny the potential and development of these exciting new materials. And in the rarefied atmosphere of F1 of course these are the materials of choice for so many structural parts.
But we have all seen F1 cars touch, and wheels, wings etc. instantly part company from the car.
Having repaired a LOT of damaged motorcycles over the last 40 years I prefer the inherent failsafe strength and repairability of a steel frame over an alloy one, an alloy bracket over a CF one, and so on down the line.
Of course my Ducati is covered in carbon and other lightweight materials, but as one who does high mileage, often in very isolated areas, I think there is a case for some degree of conservatism in these choices for major structural components.