Notre Dame brass has said that we they will continue to play Navy as long as Navy wants.
During WW2, Notre Dame was very close to shutting down due to low enrollment. Navy opened up a training center at ND that kept the school open until the war ended and enrollment returned to normal levels.
"Notre Dame has since extended an open invitation for Navy to play the Fighting Irish in football and considers the game annual repayment on a debt of honor." -wiki
Not to mention the $$$ that Navy rakes in playing ND every year, glad we can do something to help out the service academies.