I used to work in callcenter technology. We actually had a feature in one of our systems to make the customers wait even if there were agents directly available. Why? To get them accustomed to long waiting times, discourage them from calling all the time. It is really sick. It was like a fake waiting queue. It could even generate fake messages saying "there's x customers before you".

Of course the companies that wanted to implement this features were the awful ones you shouldn't want to work for or do business with. The ones that abhorred the feature were the ones that cared about customers and employees (usually more EU-centric companies).