also with altcoins that have an even lower marketcap this would work even better,so why dont we see big money players pumping and dumping?
Do some math and imagine buying up $10 million worth of bitcoin to what price would that take you?
Then add up the entire buy walls which will show you how much you could get if you cleared it out (sold in to) but doing so will kill the price in the process.
In short it will be extremely difficult to achieve what you talk about, in 'theory' that would be nice but not really possible as far as i am aware, But you could do it with a smaller amount and still make awesome money just like whales are doing every day