First, no you can't. The only 2 models available are for the Note 4 and the plain S6. Second, a contract phone is financed, you pay full price for it over the course of your contract. Otherwise you can go to a store and get a PS4 for $0 with 12 month financing, or using a credit card or whatever.
A mobile phone is not a console. It is not competing for the same users and history have repeatedly proven this. Mobile is the land of micro-transaction, compulsive gambling, and pay to win. Console is the land of $70 AAA games with high production value. The overlap exist but it remains small.
You twist everything with a mental gymnastic I can't even begin to describe, it's like you first decide what conclusion you wish for, and then work your way backwards.
I think the problem is how we think of phones.
People are going to buy phones regardless , you have tweens with the newest iphones and galaxies . The phone itself will be used for a myriad of reasons . The $100 would be the dedicated to the gaming.
The ps4 will play triple A games sure but just look at recent games on the ps4 . Star Wars Battlefront is 1600x900p and struggles to keep a 60fps average . The system is struggling to play this generations games.