The head gasket was fixed
The head gasket was fixed nearly a decade ago. The engine was redesigned. The new FB25 engines (used in all new non-turbo subarus that are 2.5L) is now a semi-closed deck design with its own cooling passages that keep the engine much cooler and provides more support around the piston cyclinders. They also now use a double metal gasket. The older engines were open deck and used a flimsy gasket, over time and constant use these were prone to fail.
Also as far as I remember the head gaskets were never an issue in the turbo model engines because they were always semi closed and used a thicker head gasket.