One man can not do anything but the whole people that are intersted in bitcoins can.
yeah I agree with you I think even if you're someone who has a very large capital and you aim to manipulate the price of bitcoin, it will not be all you can do because you would need a team, there is a lot of work you have to do at the same time when you want to manipulate price, you will not be able to do it alone?
but i think such a big number of people cannot agree on one point, therefore it is not so easy to manipulate the price of bitcoin, it really need a very big investment to so so.