PS4 will be second best and Switch will be 3rd best.

Switch isn’t a home console, it’s a hybrid and it’s already the best selling hybrid because it’s the only one ever released. But going at current trends I could see it beating the PS1 and Wii. But anything could happen. 

Is this a prediction ?

It still counts towards home consoles sales and no it't, not the only one ever release. SEGA Nomad 1995. It was a home console handheld hybrid. You could take it on the go or plug it into the TV with a second player port.

If this doesn't happen then Sony will have done something majorly wrong in the next two years.

Exactly, even if it failed, it's the first hybrid to be released.

well.. the biggest Games-Flood ever = is coming on PS4. So, maybe yes.

I updated the name of the Thread, Stepping up the game. 

With 73.6 millon sold, I believe that It will reach PS1 Level before Black Friday 2019, probably a couple of weeks before it, but not much more than that becoming the 2nd best selling home console. If I´m wrong I would be gladly surprised. 

Also It will reach Wii Level arround week 38 of 2019. 

Also before Black Friday of this year it will get past PS3 and XBOX 360. 

Getting the 1st place will be really hard, and depends on several factors. Specially on PS5 launch date and price. 

From the looks of it, the 2nd highest selling home console is the PS1 at 104 mil, so with the PS4 at around 37 mil I think it'd quite doable in almost 2 years. Seems like a safe bet.

31 millions in the next almost 2 years seems possible