Because they think they still have an option to pass the cost to companies like Google and Netflix and then use that money to increase their business and hence

Because they think they still have an option to pass the cost to companies like Google and Netflix and then use that money to increase their business and hence have an opportunity to provide good service... which is much better than investing in better infrastructure and customer service and then trying to get customers to pay more. Once they realize that internet companies will continue to use propaganda and not let it happen, they will have to take another route... which will be to keep providing the same service and keep maintaining their monopoly.