Because one of the main issues with negotiation is that people have different idea on what's a good salary depending on their educational and cultural background, the environment they grew up in, etc.
For example a company might be willing to pay up to $175k for a certain dev position. This amount of money seems completely crazy to a developer who comes from a poor family and is the first one to have a skill that can pay so much. It will never occur to them to attempt to negotiate for this amount, because even $90k seems like a great salary compared to what their parents had. $175k would seem unreal, especially in a country where talking about money is taboo.
But if this number can be seen often in ads as an upper range, it becomes normalized in the eyes of everyone who is applying for jobs, no matter their educational and cultural background.
For example a company might be willing to pay up to $175k for a certain dev position. This amount of money seems completely crazy to a developer who comes from a poor family and is the first one to have a skill that can pay so much. It will never occur to them to attempt to negotiate for this amount, because even $90k seems like a great salary compared to what their parents had. $175k would seem unreal, especially in a country where talking about money is taboo.
But if this number can be seen often in ads as an upper range, it becomes normalized in the eyes of everyone who is applying for jobs, no matter their educational and cultural background.