If the movement of bitcoins can be easily predicted and people will sell bitcoins at high prices, then who will buy those high priced bitcoins? It would be naive to think that once ETFs are approved the price will increase and the whales won't know about it? This is the financial market, my friend, where we take money from each other, not bitcoin that creates money and gives it to everyone for free. The market is like a battlefield, you need to be more alert if you don't want to become prey to others.