Single vs Multiplayer

From several years we can see increasing amount of games without single player campaign. Or treating single mode only as an addon to online play. But why?

In my opinion promoted superiority of Multiplayer over Singleplayer is bulls***. Let's think what is not included in online play. Engaging plot and well written, interesting characters are something that you won't find in multiplayer game. I'm not claiming that this is in every campagin but neither round in CoD nor raid in WoW won't give me such emotional connection with the character as few hours in Beyond Good and Evil, the Witcher or Tomb Raider.

Just look at the success of GTA or Skyrim.

From the other hand what is not included in single? Better AI of alliance (but not always :P ), everyone in the team is equal (unless you are a healer), possibility to create own story, not based on scrips etc.

But my question wasn't "What is better?", but why developers prefer to make multiplayer games.

If you don't know the answer, the answer is always the same - money.

Simple calculation - you don't have to employ scriptwriters, create cut scenes, hire Gary Oldman for voice acting, programm AI or advanced scripts.
Also we can forget about piracy problem - as long as you control the servers - you control everything. Pure profit!

And what player is receiving? Possibility to have his a** kicked by young cyber-gods that - since doesn't have job, wife, cat/kids to feed, or car to fix - spends more time for training that I spend for sleep. Cool perspective but I prefer to feel glory as savior of the galaxy, or cold satisfaction after taking revange on murderers of my family/wife/guinea pig.

The multiplayer is important and for sure can give you different kind of fun. And I'm telling this as a great fan of single mode. But I can't believe that I'm the only one that prefer playing alone!

And what is your opinion? Should there be more single player games, or you prefer multiplayer battle arenas?