On the other hand, groundbreaking innovations are often made possible by incremental innovations in other areas (such as the improved precision of steel machining tools allowing the creation of cost-efficient gasoline engines).
Yes, continuous improvement is the key to make a new technology become economically efficient, but also it may become enabler as you've mentioned. Though, by breakthrough we usually mean a change of principle how the same objective is achieved better/faster/cheaper etc. This is qualitative change in the first place. Then continuous improvement starts.