For whatever class of company, I am puzzled why is it wrong to assume marketing and sales cannot be outsourced. Marketing allows work to be done in flexible tim

For whatever class of company, I am puzzled why is it wrong to assume marketing and sales cannot be outsourced. Marketing allows work to be done in flexible timings, for sales and support one will require employees to be awake at odd hours, specific to their customer's time zone. And, I have personally seen it being done successfully - not in an outsouring company, but in an India-based product company. I believe that as long as there is going to be considerable cost arbitrage to be taken advantage of, there will be outsourcing. Development / sales / marketing - anything that does not require direct visit to customer premises.