NFS Payback coming to steam?

I was shocked when THREE Need for Speed titles was released on steam today! Can't believe it!!! So Heat, the 2015 reboot & Rivals was released & I'm confused why EA did not release Payback alongside the 3 nfs.... It's on sale today @ 60% OFF or half a price.... But the question is... Why didn't EA released it on steam, I mean it's a good game with great graphics, storyline, gameplay, & customization features... So anybody knows when will Payback be released on steam?