It can be absolutely happens that there were price manipulations, mostly who can afford to manipulate the price are only those big investors, because every prices on cryptocurrency coin are base on the total volume of stocks, and if stock market are too much higher it will result price dropping and likewise when crypto coins stocks are lesser it will also develops the price become higher because of too much market demand.
I agree with what you are saying. But one thing I want to add is that in order to manipulate this market, big investors have to shake hands together to do so because the market capitalization at the moment is not small.