Wrong toe will wear out both tires.
One tire only, is a camber problem. The cause of that could be like like fourfold. My guess is the upper control arm has slipped it's adjustment. This is a common occurrance if new cam-bolts have recently been installed. The thread on the Moogs is not enough to properly compress the stack. My cure for that was thick hardened washers installed one on each side of every bushing; the one under the bolt head and the other under the nut.