PS4 might sell 19-20 million this year, maybe more. But it's probable that it starts to slow down in 2019 beyond. The Switch on the other hand has only started out, and has many years left. There are those who already think Switch will outsell PS4 this year but assuming it doesn't, I myself think this is the last 18+ million selling year for PS4.

Do you think Switch will take the reigns as sales king in 2019 and going forward?

It's not even sure that the PS4 will outsell the Switch this year. Sure, PS4 is in front for now but a) it's tracking well below last year's sales despite the release of such great sellers like God of War and Monster Hunter World, so it will most likely not sell as well as you might expect and b) Switch had a rocky start this year with barely any high profile releases, but starting with Mario Tennis Aces the bigger releases are coming in for the second half of the year and culminating in a Smash and Pokémon 1-2 punch and possibly a great black Friday deal for the holiday season. 

With both Smash and Pokémon in this holiday season this holiday season will belong to Nintendo. Sony needs to build up a sizeable advantage in sales to fend off the assault from Nintendo, even with a probable pricecut for the PS4 in the meanwhile. 

It's not even sure that the PS4 will outsell the Switch this year. Sure, PS4 is in front for now but a) it's tracking well below last year's sales despite the release of such great sellers like God of War and Monster Hunter World, so it will most likely not sell as well as you might expect and b) Switch had a rocky start this year with barely any high profile releases, but starting with Mario Tennis Aces the bigger releases are coming in for the second half of the year and culminating in a Smash and Pokémon 1-2 punch and possibly a great black Friday deal for the holiday season. 

With both Smash and Pokémon in this holiday season this holiday season will belong to Nintendo. Sony needs to build up a sizeable advantage in sales to fend off the assault from Nintendo, even with a probable pricecut for the PS4 in the meanwhile. 

I very much doubt that. 2017 had mario kart, mario odyssey, zelda, and splatoon 2, along with switch  being a new hot product that was supply limited till near the holidays, switch won't be dominating anything, probably in japan it will.

I very much doubt that. 2017 had mario kart, mario odyssey, zelda, and splatoon 2, along with switch  being a new hot product that was supply limited till near the holidays, switch won't be dominating anything, probably in japan it will.

Why are you using games that released in Spring/Summer last year when hes talking about holiday lineup?

And you expect Sony to sell another 15 million units next year?Even when the PS4 would have probably passed 90 millions and be extremely close to 100 millions?You need to understand that there is eventually a saturation point that every console eventually reach.There are so many humans in the world interested in videogames that you can sell your console to.The high quality gamesthat are still going to release on the PS4 this year, like KH III, RDR 2 and so on, will move consoles, but wont move as much as they would normaly if released early in the console life, simply because thew audience for said games already has a PS4.PS4 is an amazing console, but its not a miracle worker.

Im not even going to adress the Switch factor here, given your bias against the company.Even if I pointed out that Nintendo is far from being empty on ammunition, since there is still Animal Crossing, 2D Mario, Bayonetta 3, a core Pokemon, new IPs and so on left, you wouldnt still acknoledge those circunstances, to put it lightly, and you will keep claiming as you were last year, that Nintendo already burned through most of their franchises,.So I believe that just pointing out the Sony factor as enough proof should be adequate, and spour a better discussion.