At the size of a national economy, you're right, bitcoin P2P network would be managed by Big Players (albeit algorithm-sanctioned participants, not government-sanctioned participants).

With regards to anonymity, see http://www.bitcoin.org/wiki/doku.php?id=anonymity

While bitcoin addresses are randomly generated cryptographic signatures, not obviously associated with any one person, the entire block chain is publicly readable, and you can readily see transactions between any bitcoin address: http://theymos.ath.cx:64150/bbe

Thus, "anonymity" must be in quotes. Even if one follows the recommended practice of using a new bitcoin address for each transaction, statistical analysis can be performed on the public transaction data.