The Power Rangers franchise has now been running for 30 years, with the classic Mighty Morphin Power Rangers still being the most iconic incarnation. For as popular as it was, however, all good things always come to an end. Thus, the first take on the series morphed into a new form that was stronger than before, though it only did so after some of the series' best promotion ever.
Source:https://www.cbr.com/power-rangers-zeo-franchise-best-build-up/