Backward compatibility is not just a game console issue. Other technologies suffer a lot from being compatible with previous developments – and so is the case of television. When color television was invented, the system was somewhat limited in its capabilities being that the signal had to be compatible with both the new color sets as well as the existing black and white televisions.
Since then, television technology has had to remain compatible with previous, somewhat ancient, generations. That's why more than a century after the cathode-ray tube was invented, we still have interlaced signals in television. Computer and television signals are far different and over the last twenty years, television has been trying to catch up with the latest computer advancements.