Champion Picks and the Developing Meta

Today, I would like to touch on a controversial subject, that is viewed differently by different people. There seems to be a common misunderstanding about champion picks in relation to the meta, and why you pick what champion when. This can lead to arguments, often in lower elo, about picking a certain champion versus another. You may even see very low rated players offering advice, so as to say something like,"What? Why would you pick lux against zed?" or "I always win lane as X champion vs Y champion."
Now, I am not going to specifically say that counter-picks don't exist or don't work across multiple tiers, but when theorycrafting a matchup, there are multiple things to consider. The most important thing to consider is that if a matchup works in your favor on paper, this assumes you are playing optimally and not making any mistakes. Most importantly, your own personal skill with certain champions, your ability to pull off different strategies, and how this relates to everyone…
Now, I am not going to specifically say that counter-picks don't exist or don't work across multiple tiers, but when theorycrafting a matchup, there are multiple things to consider. The most important thing to consider is that if a matchup works in your favor on paper, this assumes you are playing optimally and not making any mistakes. Most importantly, your own personal skill with certain champions, your ability to pull off different strategies, and how this relates to everyone…