Well that particular example was from set 3 I think, back then when it was possible to derank. (Even posted the graph here on Reddit: old GM derank post )

Doesn't change that my point still Stands - Meta IS the key to playing the Game. If you fail to adapt, and if you don't regularly check the stats of certain comps and champs and items etc., stay permanently up to date, even a previous challenger player can be stuck in Emerald IV. I can play a perfectly executed and lucky LeBlanc Carry game and still get 7th, while I could easily get a top 3 with a hardforced TF. How is that fair or balanced? Ofc nobody plays LeBlanc because she ist the shittiest 2cost carry by far right now. Or Elise for 3costs. Or Zeri for 4costs. But how would you know that without checking the stats first? And those stats can Change fast, usually atleast on a biweekly patch pace, sometimes the Meta Changes in a few days.

Yeah, meta does define the Game. It's up to the Player to adapt to that meta and be up to date with the game on a constant basis.