total recall - Why was film's setting changed from Mars to Earth in the remake?

In the first movie (1990), Douglas Quaid dreams of Mars and a big part of the story takes place on Mars. Even the Philip K Dick story We Can Remember It for You Wholesale is based on Mars. But in 2012 remake there is no Mars.

Was there a reason that the setting was changed from Mars to Earth?

Answer

Because Hollywood.

There's an interview with the director available which discusses this; the relevant excerpt is:

MTV: Will we see Mars?

Wiseman: We won't see Mars. And I got to say, it's one of the things that attracted me to the script, because I really, I along with a lot of other people, I really loved the Verhoeven film. I was very skeptical on just the reboot, just the idea. And until I read the script, with a lot of speculation going, it takes it in such a different direction from that film. Because it didn't go to Mars, funny enough, is why I was interested. And it's also just like I said: It plays a little bit into the threat of what the Philip K. Dick story had of, much more of bringing the threat back, really Doug's mission to save Earth, not Mars.