Why did they stop making smackdown vs raw games?

If you mean why they stopped the Smackdown Vs Raw series and just changed it to "WWE", then I think most likely its because in late 2011 WWE ended the brand extension (which was the thing that seperated Raw and Smackdown's rosters from each other). So now there's basically no reason for it to be named "Smackdown Vs Raw" anymore since there's no more hype or hostility between the brands like there was in 2004-2009. (I hated this decision by the way.)