The PS4 is doing very well for Sony even though the console is long in the tooth. The console continues to sell robustly and analyst Lewis Ward, a researcher with IDC, says that the console will probably hit 100 million units sold in 2019. That would mean between 2018 and 2019, the console would need to sell another 30 million units. PS4 sales of an additional 30 million sounds quite reasonable. As of early December 2017, the PS4 has moved 70 million units.
The new PS4 Pro is certainly going to help push the console to 100 million units. That Pro version is a stop gap to give 4K TV owners and fans wanting more processing power something to tide them over until the PS5 rolls out. Ward had something to say about when he thinks the PS5 will hit the market.
Ward said, "Right now I think PS5 and the next-gen Xbox will arrive in 2021, but that’s really just a tentative placeholder in my forecast."
Looking forward to the PS5, it's hard to think of what the console might bring that the PS4 and PS4 Pro don't offer. It would be a bad thing in many opinions if all the PS5 brings is a bit more processing power and support for higher than 4K resolution, this is essentially what the PS4 Pro is. Ward had no guesses what the PS5 might offer gamers.
As for the competition to the PS4, the Xbox One, it is still lagging far behind the PS4 in sales numbers. The PS4 has so far moved nearly twice as many units as the Xbox One. If you are wondering how PS4 sales compare to sales of the PS3, that older console moved 80 million units in its lifespan.