But do they really?
Where was the PS1 when the PS2 was released and how many did it go onto sell after.
The PS2 to 3 was weird in that the PS3 stumbled out the gate and the PS2 was a casual (and third world) power house.
The PS3 has only managed like what? 5 to 10M sales since the PS4 released?
Yeah it sold around that after ps4 released. But there are things to consider, like people being already tired and hungry for a new gen as ps3 was out 7 years unlike previous gens. It also never had the kind of domination ps4 has had until now. Then you have other things like price, I remember ps3 was always kinda expensive, I guess because of the way it was built. Oh and Sony seems to be pushing a lot more in China/asian countries and south america (here ps3 was expensive until they stopped selling).
idk it's just a hunch anyways, they still have a big stuff coming and there' the possibility of a new grand theft auto before the gen is over. In any case, I just said they had better legs than Xbox and Nintendo from what I remember, not that every console sells 30+ millions after a succesor is out