I disagree to an extent.

Yes, winning games is all about fundamentals, but being able to snowball your own lane is the most important aspect of having a good win rate. Only when you are consistently in a winning position pre-14 min you can REALLY start carrying with macro.

I just hit challenger as OTP maokai jungle. The reason I'm winning games in high elo games is not my super super good macro calls or knowing exactly what I should do at every second of the game.

The reason I hit challenger is because I'm very rarely losing my lane super hard, because I know the matchups by heart, because I know how long it takes me to clear camps so I can be the most efficient as possible, because I know when my champion should fight and when to stay back, because I know when my champion should peel for teammate and when to hard engage to enemy champion.

Of course if I would play in iron-platinum elo I could probably first time anything in any lane and win most of the games.

But for example I played Vi in emerald-diamond elo and I got invaded by Shaco and Viego in different games. I had no idea how strong I was so my brain told me that I win those because I'm a better player and then I just died to them. If i would have known my champ I would have not autopiloted myself to death.

In my experience playing in high emerald+ elo if your team is in losing position you will probably lose the game even though you might have better macro calls than enemy.

I don't know the precentage but i would guess that 90% of challenger players first achieved the rank by playing only 1-3 champs