There are a lot of flaws with bitcoins, and it pioneered cryptocurrency. But do we still dial up to BBSes today? Use gopher? No, it has being replaced by the world wide web. Bitcoins will be replaced, don't put your life savings in.
Bitcoin is not just software. Bitcoin happens to be a protocol, and as it becomes more popular and entrenched as
the de facto cryptocurrency, it will be near impossible to replace it with a new cryptocurrency. It's called the network effect. If people can't be bothered to try a different social network than Facebook, they sure as heck are not going to be bothered to switch to a new cryptocurrency (and certainly not on a whim).