It's possible that the same people whose lives were changed by their bitcoin business can also be the one that's going to destroy bitcoin. Keep in mind that it takes just 5 minutes to switch from using bitcoins into using a different cryptocurrency. If a different coin prevails, bitcoin will still not vanish. It will still be there but the user base will be lessen, and the price will be lessen as well. We all know that the user base of a cryptocurrency is the coin's foundation
If something can (potentially) happen it doesn't mean that it will
An asteroid could wipe life from Earth within seconds but does it mean that we should take into account such a possibility (which is still not zero, just in case) in our daily plans? And it is essentially the same with Bitcoin. Indeed, people can dump their bitcoins within minutes and buy some other coin, but how likely is this event? I don't think it is very useful to consider such events up to a point of preparing for them (since you will obviously fail to prepare for events which are more likely to happen)