After seeing Elder Scrolls Online, Final Fantasy 14 and GTA Online flop, I think a lesson can be learned.
Yes a deathmatch multiplayer suite like GTA IV, Gears of War 3, Halo 3 and The Last of Us can be done perfectly fine by most mainstream companies, but to have a dedicated MMO experience takes a company that can actually make one.
PC companies like Blizzard focus on online play, which is why they don't release new games often. They focus on maintaining games so they're fun 10 years from their release date rather than churning out new titles every year.
In order for TES, FF and GTA to have the onlines they need to be made by dedicated companies that focus on online. Otherwise, stick to single player or simple deathmatch