Someonewhoknows says it more eloquently, but basically he switched because he's a whore.
Think that may be a touch harsh. He's a media person who employs +/- 50 full time people and has a lot riding on his success. Thats a lot of healthcare, paid vacations, 401k's, salary, etc etc to worry about each month. Someone comes along with a sponsorship, you would listen too. And I promise they didn't sign Scott, they are sponsoring all his classes, videos, workshops, etc. He doesn't "have" to change but to be honest, yes he does. Race car driviers don't have to drive the car they race for on their day off but they do. Bruno Mars can drink whatever soda he wants but I promise you won't see him in public with a coke cola. Thats the way the game is played. He's not an artist. It's no different that a working photographer taking a job to shoot for a healthcare or sports company. They pay you and tell you what they want/expect. Same deal here. Whore is an easy word to throw around anomously on the internet but expecting something for pay is hardly whoring ones self.
FWIW Since Scott has changed has his work really improved? He still does the same long lens shot of someone holding up their helmet and a 600mm closeup of someones face just like every other amatuer would if they got to go on the sidelines. Don't think a D4 or a 1dx really matters.
They are all tools,...cameras, paints,..the stove used by the world renowned chef