A lot of the "value" of the miles is also determined by the value of the time you have to spend tracking miles, checking out bonuses, calling the reps (and calling them again, and again) to find out if an upgradable seat has opened up since you last called, etc. If you have a lot of time on your hands to do this, or don't mind it, then on balance FF miles can still be a good deal. On the other hand if you could be earning $400/hour practicing your profession, or have very little free time in your life to spend with family and friends instead of talking to reps on the phone and tracking these things, then it may not be worth it to you, especially if you don't fly often enough to make the other perks of status worthwhile (e.g., early boarding etc).