And if Dorier's right, signature aggregation, a change championed by Wuille that mashes
signature data together allowing more transaction data to fit into each block, could be one of the next bitcoin improvements.
Today, a standard bitcoin transaction records both transaction and
signature data together, with the signatures accounting for approximately 60 % of the data size.
Likewise you can say «Yes, but I can build a system where participants have shared control of
data by getting some databases, connecting them
together with APIs, using some digital
signatures, creating a consensus mechanism to resolve race or double spend conditions, etc etc» but you will have designed distributed ledgers.