The general impression I get of the trends amongst the (UK) kids in the schools I've worked for (no, I'm not a teacher before you ask) is that while you might get a small number who instantly watch something because it's the kind of thing they like, shows tend to become more widely popular due to word-of-mouth generating a buzz about it. Kids coming in every Monday morning excitedly explaining to their friends what happened in the last episode (complete with lots of bouncing up and down, arm-waving and wooshing noises). Kids going to play at their friends' houses and having a go with their cool new toy. It takes a lot of time to get any momentum going, but once it does it really becomes something of a craze. So even if Kyoryuger is going to be the great Sentai revival show, I can't see it doing it in three weeks. It's going to take a while yet. If the ratings are still finding new lows in the second quarter, then we can say it hasn't found a new audience.
Even so, I thought that the "Hibiki screwjob" had made it clear to everyone that the toy sales were priority number one? If that wasn't clear enough, the final clincher should surely be that the only official statement concerning Go-Busters' performance regarded its' toy sales. Regardless of what you think of Go-Busters as a show, is it really any wonder that the toy sales figures had dipped when it lacked a collectable gimmick and IMO clearly lacked a simple, sellable central theme (like pirates or dinosaurs) for its' product line (the suits have animal designs on the helmets. The mecha are animals that were more commonly advertised seen on-screen transformed into vehicles and humanoid robots. The weapons are transformed from binoculars and old-fashioned cameras). Yes, if Sentai started tumbling down the top ten boys toys charts, it would be a big worry (each position is worth millions of yen) and questions would start being asked (assuming they haven't been already after Rider overtook it). But if the toy sales are still strong, and that's clearly the primary metric they use to judge results, I'm not going to be concerned about the franchise just yet.
I don't think Akibaranger really tells us anything about the potential for aiming future Sentai at adults. It was only 13 episodes long, and even then they re-used a number of the monster suits, suggesting it was probably on a lower budget-per-episode than the official series are. It looks more to me like Toei putting a lower-level investment into aiming a product at the peripheral hardcore fanbase to tap it for more cash. That may well have succeeded (hence the second series) but it's very different to having mainstream appeal to other age groups. After all, the hardcore toku fans alone weren't enough to bring in good numbers for the highly retro (but apparently less appealing to kids) Gavan movie. Garo may bring in good money by it's own standards, but it's generating only a fraction of what Rider and Sentai shows are expected to bring in. Ultraman's reputation in Japan appears to be far less age-specific, but even it hasn't been able to reverse back from kid-focussed to a more general appeal. I have to wonder if Sentai, currently aimed at three-year-olds, would really have much more success?