Thank you for this insightful post, which gives a clear snapshot view of the state of scalability and ongoing efforts.
Exploring all theoretical options for achieving scale a little further (you mentioned sharding and combining on-chain and off-chain hybrid apps already), there may be a way to increase scalability by defining hierarchical chains. I’m thinking very much in draft mode here, but a chain could authenticate against another public sub-chain instead of just previous blocks. That way, you may be able to implement tamper-free “sub-transaction links” where the sub-network of equipotent peers that operate that sub-network are decoupled from the parent network.
Jochen Leidner, PhD
Director of Research,
Thomson Reuters R&D London