What this tells me is that Sony plans on getting the PS5 down to as low as $199 by 2022/2023 at the latest.
That's the only way I see this kinda prediction coming to pass. You wanna push numbers like those that quickly, you have to be at $199.
I think people would be surprised to know that 6 years into the life of the PS2 it had only sold 103M. Here are some other fun facts though...
PS2 launched at $299
19 months later it dropped to $199
12 months after that to $179
12 months after that to $149.
Basically, in 3.5 years the PS2 was at half its launch price. 50% cheaper.
Almost 7 years on, and the PS4 is still only 25% cheaper than its actual launch price. Bt has somehow managed to sell over 112M units.
If sony can get the PS5 down to $199 within its first 36 months, I don't see it not being able to ship 120M units in 5 years.