MMPR was the most iconic and most famous because it was the first season. Kids loved it, a lot of parents hated it and the toy industry made a mint off it. When most non fans think of PR, they think of MMPR (unless maybe they have young children currently watching a new season of PR). But why is it so popular?
When you ask a non-fan about Power Rangers, it would be something about Mighty Morphin' Power Rangers, and every Power Rangers parody is based on Mighty Morphin' Power Rangers.
When Disney did a poll for the five most popular Rangers, the only non-MMPR to make the list was Andros. Not a single Disney Ranger charted. In this case, first production company wins. That's easy to explain. The original Power Rangers used the same characters and actors from year to year. This made them a lot more recognizable than when the cast changes from year to year as in the later seasons. Usually, it would either be:
- MMPR is the best (First show).
- MMPR-PRIS is the best (First era).
- MMPR-PRWF is the best (First production crew).
(Someone's probably gonna shoot me because I used an image from the remastered MMPR.)
The first incarnation of anything that's wildly popular is usually the most memorable and ingrained into the public psyche, since it's what made it wildly popular in the first place. Then it lasts for two or three years and/or two or three incarnations that are of comparable success, then from then on it's diminishing returns, unless the franchise sticks around long enough to make a comeback (and even then it still remains in the shadow of the original). It's a pattern that works with almost any pop culture phenomenon you can think of, unless the second incarnation/second season is regarded as an abject failure.
The "big push" only exists with MMPR because it was the first of it's kind. Nobody had seen something of it's kind before. Once that became passe, it stopped being a big investment.
The franchise had sizably peaked by 1995 and was killed by "they changed it, now it sucks" with the cast and name changes, there's always backlash with an aging series that goes on without a break....there's more backlash to be had when that series jettisons it's entire cast of veterans.
From a marketing standpoint to the entire world, you couldn't go without knowing what MMPR was. It was a cultural revolution for our generation. EVERY child had watched the show, played with the toys, or pretended to morph at some point. Power Rangers hit the world just as hard as the Ninja Turtles, Pokemon, and Hannah Montana. It was the hottest ticket in existence. Once that fever subsided, there were a ton of kids who never knew anything about a "Zeo", let alone their parents. Furthermore, the majority of human beings have no idea Power Rangers still exists. There have been cast members who got calls from their agents to audition and replied "That show's still on?"
As far as people like us, however, people who never stopped loving or returned to loving Power Rangers hold MMPR in great nostalgic value, while not necessarily liking that iteration the best. I bet if there were a poll conducted over the most popular season amongst veteran fans, Zeo would probably take the title, with Space a possible contender. Even Time Force or Dino Thunder may slip in there.
Looking back, I can see why MMPR was what drew a lot of us in. The plot was simple: Bad guys are threatening Earth, and the Power Rangers have to stop them. Rita had no reason to be attacking the Earth besides conquering it. She wasn't looking for supplies for some huge diety. She wasn't serving anyone (initially - later seasons would build the evil side to the UAE of Space) and her whole army was either already released by those astronauts in the first 5 minutes of the first episode, or they were made from clay. All she wanted to do was defeat the Power Rangers, and that was IT. It's brilliance in its simplicity. Also, the blood-pumping theme song that says 'We're the Power Rangers! Shut up evil! BIZAM!' and, excuse my language here, the kick ass music of the Mighty Raw is about half the reason the original series is so great! It didn't act like a high drama like Lightspeed or Time Force, that's probably why fans are turned off by this. Like, if people wanted to watch a high drama, they shouldn't be watching Power Rangers. Because Power Rangers is a kids show, always have, always will. Granted, those seasons are amazing, but that's what people prefer.