Why does Canada still have Queen Elizabeth as its head of state?

I don't want to sound like an Anti-American here, but we canadians didn't really value our independance as much as the Americans did, and that's why we are a constitutional monarchy and not a full republic. during the american revolution, loyalists would actually move north to what is now Canada so that they would remain loyal to the british monarch. We still have the Queen as our leader because it is part of our history, but she is but a figurehead, and has no power over Canada (and other commonwealth countries.