Whoa there. it took them 2+ years to reach 30, they would have to sell a decent amount WW above this year multiple years in a row to reach 100 million in the next 3 years or even be near it.
Remember it took the Xbox 360 and PS4 around 8 years to reach around 90. I know both consoles are selling better, but both consoles were also heavier in the front loading department. We also know that AR and VR are coming in too expensive to change the game and add life, such as what Kinect and to a lesser Extend Move and Wonderbook did for 360 and PS4 sales respectively. Without something to add on to their lives t seems unlikely any will be at 80 let alone 100 million.
Even going up till end of life, because already both consoles have only one SKU, they likely won't have something that will boost their life spans by a great amount, they also are already being sold at pretty cheap prices. While last gen even with multiple Sku's they all got cuts or replaces with similar or a cheaper model, and price cuts did quite a bit in extending the Life of the 360 and PS4. i am afraid the current price wars will remove that benefit for the PS4 and Xbox one. Or in some countries, price war plus bundles filled with incentives.
If the PS4 is to reach 100 million it's got to either have so many games reaching double the output and grabbing tons of exclusive deals, which won't happen because Xbox one is still sell relatively close and well and brinign in tons of money sans japanese developers, or it needs something to boost people interests in the consoles like Kinect or move etc. Which won't LIKELY be VR at the price announced/rumored about.