The most obvious reason is that ID isn't a theory. It would be lucky to attain hypothesis status. For a suggestion to become a hypothesis, it must be testable by the scientific method. Creationism is not testable by the scientific method. Evidence cannot be found which points to creationism, and evidence is key to the scientific method.
At this point, the ID postulation is laughed out of the academic arena. There's no historical, natural or philosophical evidence for ID. The natural evidence which we have points to the earth being about 4.5 billion years old. The historical evidence we have suggests naturalistic and materialist origin. Lastly out of those three, our current philosophy correlates us nicely with evolved animals based on instinct. This makes evolution and the big bang theories which to date survive the academic arena as opposed to ID, whose bloodied corpse is dragged out of the academic arena.
To merely try to rename young earth ideology to make it sound scientific is dishonest. There's no way to prove young earth theory, we have many dating methods which place the earth at 4.5 billion years. There's no mistake here, no "Oops, turns out that the earth was only 6,000-8,000 years old.". It's just so improbable at this point. Young earth ideology is now entirely kept alive by the willfully ignorant, a Google search is a way to disprove that in under 10 seconds.
If a person manages to believe in ID, they have an Olympic level of ignorance, and to call them IDiots is fair.
“Five percent of the people think;
ten percent of the people think they think;
and the other eighty-five percent would rather die than think.”
― Thomas A. Edison
― Benjamin Franklin
― Richard Dawkins