It's blown out of proportion to an extent. Yes bundling the game is a plus to the company for sales etc. but COD, Maddwn, FIFA, GTA etc sell incredible on both consoles. Marketing rights doesn't really matter that much from that aspect. Destiny and COD actually sold better in the uS on Xbox consoles when you don't count bundles which was a great move by Sony. Gamers are dumb but they know that cod is never going to be exclusive
I think a lot of it is to do with first time buyers which is why in the case of long established annual franchises like COD. it's the bundles and maybe the timed exclusive DLC doing the work.
Everyone knows it's multiplatform but the advertising and bundles can sway new buyers over to one side.
For new IP's and something like Red Dead which hasn't seen a console release in a while, it would definitely help.
I remember the PS3 outselling the X360 in Amercia once in like 3 years when GTA5 came out because they had the bundles and marketing rights.
Those who have a console though would easily know with a google search that the games are not exclusive.