I cannot agree with you, bitcoin is not only a p2p currency, it is something more than that.
You have many places where you basically deposit the bitcoins on the exchange, and you put up a sell order.
It does not have to be neccesarily one investor buying you bitcoins, but they might be distributed among bigger number of traders.
Obviously, you can use only p2p transaction services, such as localbitcoins.com to just obtain bitcoins through trade which includes cash, or bank transfer.