This one's easy. Nintendo exits the hardware business as smartphones and set top boxes quickly make their consoles obsolete. MS and Sony sales plummet from where they are now. They're left fighting for scraps in a vastly more competitive market. MS takes a commanding lead over PlayStation in the US thanks to better services and more aggressive marketing. Sony continues to win in Europe. They're all dead in Japan.
Sony's online store brings in decent revenue for them, but ultimately M$ becomes the overall most profitable of the current Trinity... Next to Nintendo, whose software sales have shot through the stratosphere due to there mass appeal combined with being available on every device known to man.