Okay, so Navy beat a decent K-State team two years ago and also beat a .500 Virginia team in '17. Both bowl games, where we all know weird things happen. But, not taking anything away from Ken Niumatalolo, they won the games. Thanks for proving my point, I guess it's true that the definition of "huge upsets quite frequently" varies.
Air Force, Army, and Navy don't play that many P5 schools though.
Going back the last 5 years, these are the P5 schools that Army has played.
P5 school - Army won or loss
Duke - won
Wake Forest - won
Notre Dame - loss
Ohio State - loss
Duke - won
Duke - loss
Oklahoma - overtime
Michigan - overtime
BYU - canceled
WVU - 3 point loss
The only game that wasn't down to the write in any of those games was Ohio State 38-7.
Remember, Army doesn't not have a roster of P5 level athletes.
Main point is, Jeff Monken will be able to add more things to his offense since he will have access to better athletes and he would make a bowl game every year and likely even win the division here and there (not realistic to win it every year like Ohio State).