Originally Posted by
snic
so most of these miles were truly "free" in the sense that I didn't pay out-of-pocket for the tickets or services that earned them.
Don't forget the opportunity cost there. You chose UA as your reward path. Had you chose a cash-back card you may have been able to invest the money and get better value. And if one redeems for domestic coach seats the return is rarely good.
Nothing is "free" but the discount is certainly impressive when the game is played well.