God loving dammit. The PS2 has backwards compatibility, what were they thinking removing it from the PS3? And now they're continuing down this route? God dammit.
You have to
physically include previous console parts in your new console for backwards compatibility (except for when Microsoft used a software wrapper but not all games were supported). The original PS3 was completely compatible with PS2 games because it
literally had the essentials of a PS2 inside of it.
The PS3 Slim had the PS2's components removed. Notice how the price dropped, too? It's cheaper to make when you don't include backwards compatibility.
If the PS4 was backwards compatible with PS3 it would be crazy expensive because in essence there would be a PS3
INSIDE your PS4.