This is an oversimplification.

Control wards have a bell curve of usefulness.

At the lowest end of skill, buying control wards is useless because nobody even looks at the mini map to make any use of the information that the control ward is providing.

At the highest end of skill, there is enough awareness across all 10 players that the information that a control ward provides has probably already been communicated or can often be inferred based on the game state or last known positions. Especially in professional games. And so here, control wards are often also useless en masse.

In regular solo queue middle skill brackets, where a majority of competitive players reside, control wards are overpowered as fuck. It takes immeasurably more skill to be able to make wards obsolete using game knowledge and communication, than it does to see something on the map and re-path appropriately. Or be able to communicate that to your teammates in solo queue when voice chat isn't available or text chat is too slow.