A better question would be "how can one abandon that which one has never practiced?"
Scalia forever surrendered any plausible claim to "originalist" cred with his concurring opinion in Gonzales v. Raich:
Congress's authority to enact laws necessary and proper for the regulation of interstate commerce is not limited to laws directed against economic activities that have a substantial effect on interstate commerce.
He's right. That power isn't limited to "economic activities that have a substantial effect on interstate commerce," it's limited to interstate commerce itself. But Scalia goes the other way and claims that the power extends to items and activities which are "never more than an instant from the interstate market" (in other words, every item and activity).
Scalia has proven time and time again that he'll buy into a pile of bad precedent six days a week and twice on Sunday before he'll go with an original intent that in any way limits the power of his co-partisans to do whatever the hell they feel like doing.