If you get into the technical literature you may see lots of these important curves. You may even stake your life on one. As time goes on, some of the patients die and the curve steps down each time this happens. Note that each of these hypothetical curves flatten out at the ends. This is often seen in real survival curves, and it suggests that some patients in each of the two groups are cured or at least are long term survivors, though the odds of that are obviously much greater for the upper curve.
Survival curves are about life, death, and statistics.
It's scary stuff, the kind of thing that leaves the mouth dry and the heart pounding. Cancer is scary stuff. But sometimes by finding the best treatment you can change what survival curve you are on. Perhaps these two survival curves represent the survival for a certain cancer with an old treatment and a new treatment that has just been developed. Perhaps these two curves even represent the survival of patients who go out and find the best possible treatment compared to patients who don't ask questions.