Yes we can really help to stop the bitcoin price from falling if people will stop selling and start buying more bitcoin. But we can't force them to do so because they have their own thinking about it. And there are some people take the opportunity to buy some bitcoin when the price go dip thus the price will increase, and upon seeing the price increase they will immediately sell their bitcoin to earn some profit that's why the price will start to fall again, so it can really depends on us if the price will go up or down.
Holding bitcoin while the demand becomes high will help increase the price, thus it will be good for the trading market if everyone would do the same thing and would have enough fund to surpass the current downside of the market. But then we cannot force everyone else to hold because we have different life and need to survive. Yes, people would take the chance to sell their btc when they see minimal profits to roll over again or meet their needs. We do have different strategies and let us hope that all of us will make great profit soon.