Lol, no. Even if, for the sake of argument, I was to agree with you, you still have to admit that even in such scenario miners are still in much worse position to successfully pull that off than any big fiat holders (as the latter don't have to neutralise effects of price-drop first, caused by the initial dump). So not really well-suited for market manipulators.
it's actually doable and was what willy bot did in the past with the 1300 ath, manipulation it's all about make the other buy instead of you, not you buy everything and wait for another to dump, that is being retarded