They should be more single focused, but they aren't.
They got it in their heads that if they have multi, then people will tend to buy it new and keep it so they can not get left behind or whatever bs people believe. This means that they typically have a EULA where you give company X all your rights and your soul, and then they can turn around and pump out more and more extra map DLCs that apparently make enough money to offset having to host those severs for several years.
And the end result is what? A tacked on single player campaign that is completely lacking in every way, and a multiplayer experience that IS NO DIFFERENT FROM EVERY OTHER ONE EVER!
If you have played any game online, you've played every game online. Its the barest framework of an actual idea that the developer could get away with, relying solely on US interacting with each other (something most of the people at the tops of the leaderboards would never do in RL) to provide not just the metagame but the ENTIRE game. These companies spend millions and years of their lives just to pump out another venue for griefer, cheaters, trolls, and I supposed the rest would be noobs, to feel vaguely powerful because they got a headshot.
I say headshot because 99% of multi player games are the same game. "Shoot them in the head" but with about as much differences per IP as one pinball game differs from the next.
Put all the fancy trappings on it you want, paint it with your cast of characters, whatever. In the end its still you flipping 2 sets of flippers on a ball. Add more flippers, add more balls, its the same game.
Even in games like Dark Souls where the single player game is the focus, and they actually created with Demon's Souls as the prototype a kind of shared multi system, its still populated with asshats that get off on griefing others and will only fight using glitches and exploits that break the rules. Its a mixed bag. One hand you get the bloodstains and messages and can co-op (which I don't do) but on the other you are actively griefed by 90% of the playerbase and so are forced to stay hollow and realize that in the 3 seconds between restoration and kindling a bonfire you will be invaded 90% of the time and killed instantly with a backstab you had no way of defending against because on your screen they weren't even in arrow range yet. Or you can do what I do and disable your connection and get to enjoy the game you purchased and not watch someone else's epeen give itself another reach around.
I do however like playing with friends in games like Borderlands or Mariokart. Also fighting games like Smash Brothers where there is no ONE THING that can be exploited to give someone a total advantage i.e. unlike Dark Souls you don't typically run into people that hacked themselves invulnerable and have infinite black firebombs spewing from their heads. Its a fair fight, you win or lose based on your skill vs. theirs.
Perhaps the best multi games are ones like Tetris, where everyone has EXACTLY the same moves and pieces and the playing field is completely level. Well in vanilla Tetris anyways. I'm sure that there are all kinds of variations that involve powerups making your opponents pieces invisible or making their lines clear yours etc. if not I just gave you all a free idea.
With EA's ludicrous boasting that they refuse to allow single player titles to get developed under their comically large umbrella of ill gotten studios, its not a stretch to assume that their might be other publishers that like to feel as omnipotent and actively stifle creativity in such a way.
All you are saying when you demand multi only games it that you no longer want writing, plot, characterization, innovation, or anything resembling effort to be wasted at all as long as you are footing the bill. You just want decent net code and the barest, ideally pseudo original, context as to why you want the players to shoot each other in the head.
Meanwhile everyone else that doesn't treat games as the latest thing I can pwn noobs at, and completely disposable, will just stay with their older games that EA has turned their back on.
Believe it or not their used to be genres other than shooter, MMO, and RTS. Not for long if this poll is any indication.