I don't know when was the Bitcoin futures started but this article might explain it: https://www.coincentral.com/bitcoin-futures/amp/ and it provide details that it's relatively new. Therefore, we can conclude that futures doesn't the one that triggers the bear market. You might have point here now that we have grown and there's more institutional investors involve in this market. I don't think this will be conducive in the future if most are driven or being decisive by trading on futures or leveraged market.