when Luna started falling badly, the investment of many people sank, but there were very few who made a lot of money with future trading by opening short positions with high leverage. However, after the launch of LUNC. People did not trust it as much as before due to increasing in its supply and declining market cap, everyone thought that a short position should be opened on it so that it could make more profit or reduce its loss. Now here is a common-sense thing if everyone will make a profit then how will the market run But people, as usual, fell back into the whales' trap.
That short futures were a big big danger zone during that time. People did a huge leverage for shorting, but there were times when it did small upticks. It means that even though it went lower, the short positions were liquidated. I remember many times when it was under 1 dollar, getting to few cents and even lower, and it did like 1 cent higher price and liquidated all shorts and then kept going down even more.
This caused not many people to make money like you assume. Sure those people made money with some of their bets, but they lost money on some of their trades as well. Hence, it wasn't a clear money making method, it was a bit of a risky move.