Prior to ROTJ there was no marketing genius in the form of something cute and fuzzy that little kiddies and girlfriends would like and feel sorry for.
ANH started nasty and kept going - first thing you see of humans is a bunch of RFT's that are about to be massacred by blaster fire or had their neck snapped during interrogation. The rest of the movie is less violent but nothing cute and furry in there.
ESB is even darker, for the most part with the slaughter of infantry (i.e. Hoth troopers) going up against monstrous AT-ATs. Oh sure, they had some support in the form of snowspeeders, but that's like putting cavalry up against tanks. Nothing really cute and fuzzy in the movie, save a Wampa and a Tauntaun. One gets it's arm chopped off, the other smells bad and gets its guts flayed open with a light saber. Nope, can't market that to the kids/ girlfriends.
ROTJ is fine, until we get the surrealistic battle between a buncha friggin' teddy bears and the Imperials. Yeah, yeah, I get the allegory between good and evil, belief and imperialism. Yada, yada, yada. But be honest, those things were supposed to be Wookies. Big, ass kicking wookies that ripped arms out of sockets. But they couldn't find enough big guys to play the roles, so they went with "little people" and that brought out the marketing ploy of having valiant little teddy bears.
Fast forward to TPM - here's Jar Jar, a bumbling, harmless guy that's ultimately heroic if only by accident. He's cutesy. He talks in a manner that is funny to the kiddies and maybe even the girlfriends who aren't quite so obsessive as their quasi-normal, if not overly geeky (at select times only, of course) boyfriends. He's comic relief. But he's also primitive in a sense and facing overwhelming technological odds. It's the same damn thing as the Ewoks. The Gungans got bigger, but they were supposed to be cute, primitive and something people would cheer for, just like the Ewoks. The problem is they miscalculated and Jar Jar wasn't nearly so cute or funny to most people as they thought. But the allegory was still there, same as the Battle of Endor.
There is no way cute little furballs armed with primitive weapons spawned the jibba-jabba spewing catastrophe that was Jar Jar Binks...
You don't want to believe it, but it's true. When Medicom finally loses its collective mind and puts out a Jar Jar Kubrick, you will buy it. You have to, because you're part of the reason that it will even exist.