Bitcoin is by definition not controlled by one party. It is in all involved interests for that not to be the case, since it would immediately lose all value were it to happen. You know, slavery has also been around for millennia, but I don't think it should make a comeback.
The point about being around for millennia is more about how do you measure a system where value is placed by faith. Longevity is a measure of faith. Unlike slavery, there is nothing inheritly bad or likely to change about gold any more than about bitcoin. Intact gold is backed by physics - you cannot fake it. Gold is gold. Bitcoin is one of many cryptocurrencies. Happened to be the first but that is the only distinction vs. Say litecoin.
Bitcoin is not as democratic as you suggest. Mining pools have power. Decisions get made. People are involved. It is like saying the US is not controlled by definition because there is Congress. But those people make decisions and can be heavily influenced by those with money.
