I assume OP doesn't want to blame mobile for all the influence it has given AAA publishers, seeing as how they saw the money they weren't making just lying there on the table.
Also, what is with this weird line of logic, where every MP based game has to have a campaign, has to adhere to the SP crowd. I cannot for the life of me find an instance where a SP only player once thought "you know this would go great if it had MP", but instead we get the "it has to adhere to my desires or it should flop.
I will be very blunt for any responses toward that last part; I honestly give not a single damn about whatever excuse that is to be laid before me, that an MP game *has* to have an SP campaign. There is no grounded logic that SP has to dominate and control how the MP side of the industry functions, let alone how it thrives. I like both SP and MP, but in the case of Overwatch not having an SP mode, I couldn't care less, because it's world is brought to life via trailers, bio's, mini movies and official comics. TF2 had this same setup, and Blizzard seems to have taken that page from Valve on how to present it's characters and how to explain them to the user.
Step right up come on in, feel the buzz in your veins, I'm like an chemical electrical right into your brain and I'm the one who killed the Radio, soon you'll all see
So pay up motherfuckers you belong to "V"