Was polio going to go away "on its own"?

This chart is misleading.

It makes it appear as though polio was going to disappear without vaccine intervention, and it doesn't take into account morbidity (only mortality). The truth is that spikes in death rates can be "paused" after the bulk of frail patients (infants and the elderly) succumb to the disease. After that, initially healthy patients have a better chance at survival (i.e. don't get tallied into the death number), but they suffer SERIOUS long-term damage. Additionally, the initial spike in deaths prompted aggressive public health interventions including quarantines and the closure of crowded events. That contributed to the drop significantly, but wasn't a long term solution.

Vaccines are the long-term solution. Where polio vaccines are not given, the polio virus comes back rearing its ugly, ugly head.

Addendum: A friend of mine brought up hand-washing. Hygiene definitely improves when a plague is rampant and I'm sure this can be credited with assisting the drop in death rates above. I wish it would stay that way, too. In theory if everyone practiced the aseptic method we'd be rid of all sorts of illnesses. Realistically, however, people become complacent when the threat of disease is not staring them in the face. Also, case in point, my kid just sneezed in my face. Thus proving life and illness happen.