i think the part that everyone here has missed is that keksalot quit watching around the middle of rebooted when the love triangle got dropped in, which is fair; personal opinion (and i've heard a general consensus in the ninjago community, however small that is) is that the show takes roughly 4 seasons to use its characters in an interesting way, and that the creators really started putting more effort into making ninjago a watchable show after its "reboot"; it's a show designed to sell toys after all, and the only reason it managed to get 10 years is because it was doing it first and with some impression of real characters and the idea that they could still go in different directions (the pilots were supposed to be a one-off after all)
prior to tournament though the show is largely pretty hollow: i love the first season when i first saw the episode where zane realized he was a robot and came to terms with it, but i was also 10 and realize that even if it is one of my favorite episodes it's hardly as good as an episode from other shows, or even other episodes from later seasons. season 1 is mostly just groundwork with imo good and important key character elements here and there and but little mind paid to breaking from the mold sometimes, season 2 is fun exploits for kids and what is more or less supposed to be a conclusion, and season 3 is largely action and very little substance; but, coupling the relatively lackluster screenwriting with the relatively lackluster animation, the entire thing feels very vapid and overall like another run-of-the-mill toy commercial with moments where it felt better than usual.
then of course we get a whole season with a whole overarching arc and genuine character struggles and motives and neat fight scenes, followed by a season that (imo) sucks but visually takes ninjago to a higher level and expands the size of ninjago and its own place in the ethereal sense, then a whole character-based one-on-one duel between one ninja and one of the best (arguably ofc) ninjago villains. after a brief divot with 2017 the show went ahead and used the bigger budget and bigger scale to make two seasons that might be some of the best lego-adjacent media to date; and even now the show, despite reorienting to the 8-12 demographic, will at least get you a kinetic & engaging fight scene or fun banter or something (the newest one (13) is honestly one of the best ninjago seasons though). characters themselves are given a lot of time to develop over the focus on promoting toys, and for that matter most of the best seasons are built largely around character moments while the sets act as little set pieces for moments or get 10 seconds of screentime before disappearing entirely; to be honest, ninjago should've been the action figure theme while bionicle did system sets with how much more interesting the characters get.
so yeah, ninjago's not a perfect show overall and it probably didn't deserve its position as the next bionicle but you could argue the writers earned it: they managed to develop a solid plot after a while, the sets managed to grow in quality to where they are now (in large part because of the movie, but still), and even now there's still a lot to get from the show. the movie sucks largely because it fails to create interesting characters outside of maybe a couple and the writing and pacing is all over the place without being a little self aware about it and consequently fails to sell the show or the products by making them interesting ( i've already worked out a script that works better but this is hardly the place to advertise), but regardless the theme has managed to justify its extension and its television series with time, and my bet is that we'll see kai ninjago default dancing in 5 or 10 years like all the tahu memes. it's all in due time or whatever