You do understand that AA sells upgrades into first class, right? There is both the "sticker" upgrade program for elites and those on Y/B fares, referred to above, and the LFBU (otherwise known as kiosk) upgrade program. Why should AA give you for free what they are trying to sell to you and others?

But assume for some weird reason that AA decided to give away what they are trying to sell. How many passengers in coach do you think would like to receive a complementary upgrade into first class? And why should AA choose you over the others to receive that free upgrade?

There is a ton of information about AA already on this forum. If you read the stickies, read the Wiki, and do a search before starting a new thread (which we all agreed to do when we joined FlyerTalk), you won't find yourself nearly as often in the position of receiving answers to your questions that make it clear to others that you haven't put much thought into your question. In addition, you will learn the information required to make your AA flying much more enjoyable and profitable.