Well, some people on the right are doing more or less that, for instance by resisting the Kyoto Protocol not on the grounds that there isn’t any global warming, but on the grounds that the Kyoto requirements aren’t severe enough to reduce greenhouse gas emissions to a level that would actually stop or reverse the warming. Expect to see a lot more of this leapfrogging in future, as more of today’s climate change skeptics stop claiming that global warming is a myth and switch to complaining that all the solutions proposed by “those damned libruls” are either too ineffective, too costly, too economically disruptive, or all of the above, so the only practical thing to do is nothing.
For many climate change skeptics, though, I think the answer is simply that a self-congratulatory skepticism is easier and more fun than actually sweating through the ignorance-fighting process to learn something about the scientific issues involved. Just like lazy liberal thinkers automatically assuming that their opponents are motivated solely by corporate greed/patriarchal sexism/imperialist domination/whatever, there are lots of lazy conservative thinkers ready to automatically assume that the other side’s viewpoint can be easily explained away as mere opportunism/socialism/attacking the American way of life.
When you think you already understand the “real reasons” behind someone’s argument, that means that you don’t have to bother trying to understand the apparent reasons. You can smugly congratulate yourself on being too smart for your opponent, even without actually knowing what s/he’s talking about. And lazy thinkers on all points of the ideological spectrum are attracted to that kind of easy out.
It’s like Linus in the Peanuts comic strip faking his way through a test in school by guessing the probable sequence of “True” and “False” answers, and chortling “If you’re smart, you can pass a True-or-False test without being smart!” (The strategy ultimately didn’t work out very well for poor Linus, who turned out to have “falsed when he should have trued”.)