They haven't really been in the market for a long time so I wouldn't use them as an example. Some altcoins who have proven themselves to have survived for a long time is litecoin, eth, waves and many more. Good marketing campaign and completing roadmap is one thing, but what keeps altcoins survive long time is improvements(it keeps demand going) and it's use cases(like what others mentioned).And altcoins needs development and progress to survive in long term. not all altcoins will survive many will fall even though they have good ideas. having a good start and support of community would help altcoins active or run for a long time. also being in the top or being popular will help it survive for a long time.