You are kidding right? namecoin also needs to be renewed, and currently it's several times more expensive than just registering a ICANN domain with godaddy.
Also the cheapest price in the world would do nothing, if the whole world don't support the protocol.
Several times more expensive huh? With the current rates it costs around $7.5 usd to register .bit and it will keep on getting lower. Renewal costs $0. Meanwhile godaddy costs $12 per year.