President Bush had many conservative ideals, but he was / is a big government republican. No self-respecting conservative believes in big government. Big government is the opposite of individual liberty. For those whose eyes gloss over when hearing the term 'liberty', 'freedom', big government means that you can't do what you want to. Big government means that someone else will tell you whether you can smoke, can eat, can do.
So with the press' full-court press on redefining the political spectrum, we wind up with the most liberal member of Congress being considered left-leaning. During his ever-so-brief tenure in Congress, President Obama didn't find a spending bill he didn't like. He also voted at every opportunity to reduce the freedom of the American people. This 'tendency' has been continued at a fervent pace as president. He's on the way to socializing three industries and yet there's no cry of fowl from the press. President Chavez of Argentina has even recently commented that he believes that he and Fidel Castro are right of President Obama.
President Bush isn't at fault in this matter. He isn't a conservative, it's not his responsibility to carry the conservative mantle. His behaviour actually reinforces the belief that 'moderates' have no true believes as he didn't feel the need to clarify what or who he is. So whether the press marked him as a conservative or liberal, that didn't matter.