I see no reason they would have old ships, when they can use giant replicators to create huge pieces of structure, like 3D printing on a larger scale. And they would likely reclaim/recycle the matter from old ships to build the new ones, so the old ones wouldn't be around anymore.
	
		
			
		
		
	
				
			 
				 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		