Good TV shows are cancelled?

I have witnessed so many good shows cancelled, such as family guy, futurama, naruto, and so many more. Nowadays tv shows are all about watching immediate ratings and garnering earnings from television advertisements. Instead of watching quality TV the TV stations need immediate results/popularity which usually doesn't happen in time. Instead of having a few short commercials and then returning to the action of TV shows we are bombarded with minutes of mind-numbing ads that frankly are almost as long as the show itself. TV is supposed to be enjoyable entertainment but big TV stations are raking in huge profits in exchange for the TV shows that the viewers want to watch. I personally think that TV stations should continue airing such great shows as family guy and futurama and naruto and even the simpsons because even though they might not result in immediate profit, the viewers will be happy and over time new shows will be able to develop a fanbase. Just an example of how making a profit has affected TV, for example king of queens and two and a half men were replaced by cooking shows and reality shows that are much less popular. TV is filled with reality tv shows to the extent that most of what is on TV has become boring, pointless programming and even full hours of paid TV ads because reality shows are much cheaper and as well paid TV ads result in huge profits. The greed of these corporations has severely reduced the quality of many quality programs/shows out there. Does anybody notice that TV is simply a chance for people to make money?