So the OP wants BlackBerry to not only dump one of their largest revenue sources (BlackBerry OS BIS/BES subscriptions) but also spend loads of money on promoting BlackBerry 10 devices? Man, that's a terrible idea. Do you want BlackBerry to close their doors as soon as possible? All the advertising in the world won't make Android, iOS and Windows Phone magically disappear. As long as those other, more complete platforms exist, BlackBerry will have a very hard time convincing the masses to buy a BB10 device. So why spend the precious resources on such a gamble?
Besides, if you're Chen, do you even want everyone to upgrade from their BIS using legacy device to a subscription free BlackBerry 10 device? All legacy users are BIS users, how many people with a BB10 device is on BES?
BlackBerry is becoming a software and services business and BB10 devices sold to the masses who don't need or want BES isn't going to do much to help them in the long run.