Carbon fiber when?
The only carbon fiber reels I've seen on the market are cheap injected molded economy items.
However just reference other sports with highly stressed components requiring a high degree of dimensional stability required and high corrosion exposure. Carbon fiber has taken over, not cheap injected molded c#@$ but well designed hand laid up products.
Top end bicycles have replaced aluminum on cranks with carbon fiber, minimum breakage, highly stressed, exposed to corrosion and high cycle rate. Cranks have to be stiff and keep is dimensions (or unwanted chain slips would plague their use).
Archery is now going to carbon fiber for the riser (not just the limbs) that has high stress and critical need of dimensional stability.
I'd love to see a fly reel maker step forward with the kind of carbon fiber use that eclispes the cheap injected molded cheap reels. A truly enginnered carbon fiber reel. One that is durable, corrosion proof and light.