Time for another long-winded Bio post. Let's see if we can clear up some of this confusion
This statement is true, up to a point. As others have shown, there's a whole lot more original themes then just these two. I think what Radrix was trying to say is that there are only two original story driven themes left as he clarified later in another post.
I don't think Ninjago is going anywhere anytime soon. I believe I saw somewhere it is now considered an evergreen theme (like City) so as long as people keep buying the sets it's going to keep on chugging along
I know this is a joke and all, but I feel the need to respond to it. Unless the movies get rebooted or this new Amazon series does come to be, then I think Lego LOTR will never return, as it has no real purpose to exist. The reason Lego Harry Potter came back last year was most likely because of the new movie in the Fantastic Beast pentalogy.
Now onto the different original themes
Kind of have to agree with you on the repetitiveness a bit, but Lego is trying to differentiate things a bit. For the second point, while City doesn't really have an overarching story, each set allows a kid to create their own story
Gonna have to agree with you on this one
The same point as City, while there is no overarching story, each set allows for a kid to create their own story
Personally, I would give it an eh, as it's sort of an original theme, but I'm not sure if I would count it as an original theme (just like its predecessor Mindstorms)
I kind of have to agree with you on this one
While yes, there has definitely been a bit of an increase in licensed Technic sets as of late, I would still say, at its heart, Technic is still an original theme
It's similar to all of the different movie waves (except for maybe Batman) and Mixels (and also the Freemaker Adventures and Yoda Chronicles subthemes in Star Wars to an extent) in the sense that's in sort of a grey area where it could be considered both an original theme and a licensed theme as while the sets are all original ideas, for the most part, they appear in a licensed property, in this case a TV show or movie
In regards to why people might like why Elves ending, is because they never really fit the bracket that it was intended for (young to pre-teen girls) and therefore did not really enjoy it as much as other people did. While I've never really fit the bracket either, it is kind of sad to see it go.
Finally, in regards to whether Elves might return this year, I'm not really sure. We don't how well it sold (and probably never will), but it did manage to last for four years (1 year longer than Lego usually gives new original themes if they don't cancel them early like with G2) up to this point. We'll either have to wait until the spring or summer until we know if it's returning or not. Heck, it could even be taking a year off before returning in 2020, we don't really know