I dunno if looking at top end cyclists is really useful for the impact of cycling as purely an accessory for an amateur climber. They are combining high levels of cycling with very specific diets and, yes, drug use in order to create a specific adaptation. That's not what the OP would be doing.
Those telling people that their legs somehow didn't get bigger are funny. I guess those of us that got bigger legs must all have a vivid imagination... Next you'll all be like Tyler and claim that those finger strength improvements from repeaters were all a dream.Unlike the OP I don't find running makes my legs bigger, but I can believe that some people do
Sorry yeah you are totally right, they are using specific training for particular kinds of performance, my point is that what they are doing is so in depth, regimented and extreme that I don't think it's hugely relevant to doing some cycling for accessory cardio as a climber.