Idk why people complain about balance so much

When in game I'd say 50% of the problems are from poor item builds. For example not building (assuming you're a tank) vs a who's build is something like this or playing an assassin and not building or vs a with or .

There's an issue with balance in this game, but even so there are ways to get around it for the most part. What I personally don't like is champions still being able to carry like a 0/5 being able to 1v3. a team of moderately fed players.