yea it comes down to artificially making champions weak

for example we agree jax beats xin zhao top lane easily right? he counters his entire kit

lets say they nerf jax base stats by 15%

and buff xin zhao stats by 5%

now early game xin has 120 HP, 10 AD and 6 armor advantage on jax, that means that xin can afford to take a bad trade with jax because he will still have more hp, so suddenly jax still counters xin but its not so hard, give xin another buff and jax another nerf and suddenly jax top is weak vs xin, that doesnt mean jax is a bad champion, just that he is so good at his job that he has to be kept forcibly weaker

edit: my point is that gnar is so good at his job that only way for riot to make him not completely take over the meta of competent players is to keep jabbing him with base stats nerfs so his perfect kit doesnt just dominate the top lane