Regarding the leaker saying PS5 will is $500, on the hypothetical that his leak is true, he could be talking about Sony's internal BOM target being $500. Sony could still sell this system to consumers for $400. PS4 sold at $400 for years, so Sony knows if they build a system with a high value proposition they can retain the launch price for a long time. Just like GDDR5 on PS4, they can build a system with expensive components that are expected to quickly fall in price 6-24 months after launch.
Also, with BC built into the system, there will be no 'reset' in game purchasing habits from consumers like previous generations. The loss incurred from hardware sales will hurt A LOT less with subscriptions, games, and DLC sales not skipping a beat in the generation transition. I'm not as pessimistic as others here with Sony hardware...