In my own opinion bitcoin not totally control the market but what ive noticed is when the price if bitcoin down the ethereum and top coins also down and when bitcoin price rise its follows also and rise.so bitcoin only influence the market and not control it.
Then last week when Bitcoin went up but all Altcoin even Ethereum price also got down. So their is no correct prediction of whether Altcoin are following Bitcoin price or not. But one thing is sure that Altcoin are only to earn more Bitcoins so it is true that Bitcoin is the main coin which controls Market. Because what ever price any altcoin can go high but in the end when Bitcoin price moves up everyone will sell their altcoin to convert to bitcoin so that they can sell In BTC market and get more profit.