For me personally, this is why I dislike Hero Factory. G1 ended and HF was introduced, and I was pumped. New opportunities for new stories and characters to fall in love with, it was a fun, if bittersweet, time. However, not only did HF not have as complex a lore as BIONICLE did, but it was hard to even find the story in the first place.
The theme didn't get an annualized run of comics like BIONICLE did, the chapter books (those were a thing, right?) were impossible to find, and LEGO never made an announcement on when the TV show was airing. The idea that a LEGO theme would be receiving a tv show at the time was mind boggling. This was a whole year before NinjaGo would start, so LEGO content was usually comics, chapter books, or straight-to-DVD releases. Again, the prospect of LEGO story telling on TV was exciting, but to my knowledge, they never actually posted on the site when the show would be airing. And it was on NickToons of all places, which was essentially an afterthought of Nick's reruns at the time, so I usually steered clear of it, and thus was never able to catch commercials (which I only know exist because I've watched them on YouTube after the fact) saying when it would be on.
If I'm remembering correctly, I think the NinjaGo pilots got an advertisement in the LEGO Club magazine prior to them airing on CN. That's at least some form of a heads up, and it was enough of one that I tuned in. HF got none of that, which is why I gave up. Unlike other fans, I was never into BIONICLE for the building system. It's not what got me into the theme, nor is it what got me to stick around. It was the story. HF being BIONICLE's replacement isn't what I found insulting, it was that the replacement seemed to care so little for its story that they didn't bother to properly advertise. To this day that remains the reason I dislike HF, because, in all honesty, it still did some cool things.
It introduced CCBS, which is a great building system, that build-your-own-hero thing was cool even though I wasn't aware of it back in the day, and with the exception of that animal year and the final wave, the sets honestly looked really cool. There was just never an incentive to buy those cool looking toys because I had no clue what was going on in the story. Even when I noticed the show getting the DVD releases I had no want to buy them because by the time they were coming out, it was like two years after the fact and the story was off doing who knows what by that time.
So there's my potential Unpopular Opinion. Hero Factory did pretty much everything right except in one way, the story, and that in my mind, is why it's a failure even though objectively speaking the theme wasn't a failure because it lasted five or so years, but we'll ignore that because I still don't care for the theme .