Furthermore, while the scope of the danger is usually global, for whatever reason the evil guys of a given year tend to keep their assaults on mankind to one small city or town; presumably to move on from there, if multicolored kung-fu heroes weren't conveniently there to stop them cold. Sounds like the stuff of legend to me.
It would be interesting to read a comic book that is an alternative retelling of the first season of Mighty Morphin Power Rangers. Zordon tries to recruit the teens to become Power Rangers, but like the first time they refuse the call. However, they don't encounter the squad of putties on the way out. A few hours later the Command Center is destroyed and Rita launches her assault on the Earth without the Power Rangers to oppose her. I'd read it.