I definitely want to probe into something said here, and hopefully as somebody who doesn’t lucid dream every night it doesn’t seem that I’m being naive or rude.
You mention that the amount of “different” dreams is dictated by the amount of concepts our brains have been exposed to, and I suppose that logic is sound. But how do you define that number of concepts? I ask about this because I’ve found a lot of people that claim to have too many lucid dreams aren’t aware of what it actually means to experience everything possible in a lucid dream; we may ask about a dream in which the person did such and such a thing, only to hear something like “Why would I do that, it’s stupid/juvenile/uninteresting” or “Wait, you can do that kind of thing?”. They’ve seen many concepts, but never felt like exploring some of them in a dream, instead locking themselves into concepts they found it “safe” or “normal” to dream about.
If you have a pool of dreams that you’re pulling from and changing small details as you claim, then you could ask yourself if you’ve really, really tried to escape that small selection. Somebody that believes to have experienced every possible lucid dream based on the concepts their brain knows should readily have an answer for a completely random question about them, so I should be able to approach such a person and say “Hey, so how was it spending a dream as King Kong?” and get an answer (and if you do have an answer for that one, then I guess I need to ask a crazier question).
I really struggle to believe that people can experience every concept their brain has ever been exposed to. In the worst case, if you’ve truly experienced everything that your brain could, there are some lucid dreamers that lead a second life of sorts in dreams, with reoccurring characters and places. Another member, Faith42, had a personal world that she visited for the longest time in all of her lucid dreams, with its own special rules; some lucid dreamers have completely different forms in their lucid worlds and/or have dreamscapes in bizarre settings or with fantasy elements.
I would encourage you to look through our lucidity challenges and quests as well as the Tasks of the Month on DreamViews; browsing these would be a quick way to see if you’ve experienced as much as you think. Nothing is too crazy to be a worthy lucid dream. If I’m wrong and you’ve truly done it all, then I apologize in advance: “everything” is a difficult concept for us that don’t lucid dream as often, and I’ve found some that do lucid dream constantly that limit themselves or don’t think out of the box, so I’m asking for my understanding and for the benefit of any such people.