beyond any doubt both bitcoin and Ethereum can impact the cost of whole market everytime their value change, it doesn't have to much time to impact the market when the market relies upon their cost and a large portion of altcoins available utilizing two sets: ALts/BTC or Alts/ETH, that is the reason when the pumps or dumps happen, the cost of ETH and BTC is the main focus of whales to influence he to cost take after their aims.