According to my understanding, the bitcoin economy is small enough that all clients can have a record of all transactions. Bitcoin was designed for a truly dist

According to my understanding, the bitcoin economy is small enough that all clients can have a record of all transactions. Bitcoin was designed for a truly distributed model, but this aspect is untested in practice. It seems to me that the move from "everyone knows everything" to a truly distributed model entails a lot of risk, and it's possible that the protocol just may not work at this scale. Is this a reasonable concern?