Although kids nowadays definitely aren't as into toys as they used to be with all of the video games and social media available, I've found plenty of them still are pretty interested in Bionicle when shown it. A lot of my younger cousins (4 - 9 years old) who typically don't even care much about Lego still jump at the opportunity to look at my collection and grab at their favourite cool figure.
As much as I'd love to see a revival, I know Lego could never capture the same lightning in a bottle, and they don't have much reason to with their current success. In my eyes a lot of the charm of Bionicle was in the unique molds, plenty of weird and interesting pieces that were used in very creative ways, but it just isn't the same after Lego's crackdown on creating new molds.
Feel like the best chance we have at a G3 would probably be a short line of nostalgia bait in another 5 to 10 years. And honestly, I'm fine with that. Since we all know it will never be the same as G1 or G2, all I'm asking for is more brick-built models like the GWP Tahu, it's grown on me a lot over time. Only change I'd like to see if Lego went that route would be a few molded mask pieces.