Two things I want to point out. The 16 million for Uncharted 4 should probably be removed as it's VERY dubious. Sony's official information only has the game at 8.7 million after 266 days after launch. Sony does update other games that keep selling. Horizon shows up through 672 days with 10 million. We're saying the game doubled in sales and sold another 8 million a year after it came out? Maybe it's all bundels but I'd say that it's probably closer to 8, not 16.
See pg 9
On the sales, one thing to keep in mind is that all of these titles are releasing late into the system's life, after the system already has a large install base. In other words, they didn't move the system, more likely the system moved them. It seems more like 3rd party games pushed the system and then Sony's first party games road the wave thereafter. Fun fact, Bloodborn, released in 2015, has only sold 1 million according to Sony. We'll get a better idea when Gen 9 gets moving into high gear if their first party line up is really moving units or if the rising tide lifted all boats.
Known as Smashchu in a former life