Since at least 1997, people have been crying doom for Super Sentai and saying the only reason it still exists is because of PR. Do you honestly think Toei's making an entire show from scratch for the sake of Saban buying it to partially slash into his own thing? That seems like an awfully insufficient way of trying to make an extra buck.
Look, Super Sentai might not last forever, but it's foolish to think it's so disposable just because it's currently in a rut. Sentai offers something for everyone, plays on different levels, and is the only daytime hero show Japan has that appeals to boys AND girls. If Toei didn't treat Sentai like its bastard step child and Kamen Rider like it was the Golden Child, they could put in the effort to take advantage of its wide appeal and put to use certain demographics that Kamen Rider has never, or never will, intend to target. Sentai's versatile; you can do anything you want with it, while there are certain things expected from Kamen Rider.
It all just comes down to uncreativity. Toei takes Sentai for granted (just like most of the fandom tends to do). They try too hard to think what will appeal to kids rather than just putting out a product and letting kids decide for themselves what they think is cool. Sentai's not dead. Toei and Bandai's creativity is. Just look at the past 15 years of their toku. Something like Ryuki had that absurd, pulled-from-anime gimmick of card collecting, but it was treated as just a tool in that series. Nobody talked about the cards, nobody questioned why they were cards, they didn't write episodes about just the cards. There was a narrative going on, the show was trying to be about something. The cards were decoration. Compare that to Gaim or Ghost where the entire shows exist around the gimmick, the entire storylines being about the gimmick and obtaining the gimmick.
Ryuki took a gamble with the card thing. It was a risky thing, but it was something that had been proven to be successful in other properties, so -- as much as you hated it -- on the side of evil business, it made SOME sense. It's just dumb the way they approach the shows now, sitting around their offices. "What do kids like?!?! Uh...FRUIT! Yeah, how about we make a Kamen Rider about fruit?" "Great! But we can't sell special fruit, it rots! What can we sell?" "Uh...you know what kids like? PADLOCKS!" "Whoa, how did you come to that decision, weirdo? How do we make that a show?" "Ha-ha-ha-ha-ha, get out of here, voice of reason!"
Toei right now treats Sentai as just a way to make a little extra cash while Kamen Rider turns water into wine. They're not paying Sentai any attention, and THAT is the problem. It's not a matter of Sentai not doing well or not being good or whatever. It's the current way of thinking on the part of the executives. Rather than try to make something good, that will last, that will appeal to people and go on to be fondly remembered, they're only making a product that suits their needs for a year and will be done. There has been zero effort made on Toei's part, in terms of show content, since Go-busters. As they're on auto-pilot, they've just been putting out something new and shiny for the sake of something new today and move on.
And while I wouldn't want Sentai to force in stupid gimmicks like fruit padlocks for the sake of a couple more points on Bandai's fiscal charts, and I question just how much kids are even into gimmicks, maybe things wouldn't look so bleak for Sentai if they put more thought into merchandise beyond mecha. A couple of shows, like Go-onger, Boukenger and Kyoryuger, flirted with the idea of having collectible gimmicks on the side. But for the most part, Toei saves any gimmicks in Sentai for the mecha. Mecha's over, man. Nobody but the nerds likes mecha anymore. Give up just throwing a ton of mecha at Sentai and thinking that's sufficient. I think mecha's really outdated, and if there's one thing that Sentai needs to shed and find some new approach about, it's in finding something better than giant mecha to rely on. Toei mistakenly thinks Sentai's sole identifying marker is mecha. Toy sales are crap and mecha's never been duller or uglier. Coincidence?
I think the gimmicks that pertain to the heroes, and not their boring machinery, holds more interest. Kids want to pretend to be the heroes, not the heroes' vehicles. You think Kamen Rider sells more because it's cooler or that the gimmicks are good? ****, no! They rely on goddamn rings and fruit padlocks! But they sell because the gimmicks pertain to the act of being the hero. You slap that belt on, you fuss around with different dumb fruit padlocks, you make believe you're one of the Gaim Riders. If all an Astro Switch did was change the shape of Fourze's bike, nobody would want it.
Don't write off Super Sentai. In the '80s, when Kamen Rider was dead and Metal Heroes were dead before they started, who was still standing? Super Sentai. (Well before PR.) When Metal Heroes were totally flatlining, what did they do to try and survive? Become like Super Sentai. What has Kamen Rider been accused of trying to imitate, with its colorfulness and lightheartedness in the past decade? Super Sentai. Everyone's got Super Sentai envy, yet they still don't respect it.
