I agree with some of what you say, but strongly disagree with your opinion that upgrades/FF points are "gift's" from the airline.
In virtualy all business's that I've been involved with, the customers that represent the highest revenue/margin get the best service. Service is not a "gift". It is earned by repeated loyalty to that business relationship. (in the case of the airline business model, service = upgraded seats, club memberships, and free trips)
DL seems to be falling into that dangerous area where they assume it's easier and less expensive to win a new customer than hang on to an existing one. This may come back to haunt them with a tad bit of softening in these unprecedented load factors.
I do agree that the ultimate recourse is voting with ones pocketbook but in the case of DL, in not sure this "elite" revolt has even made it too Uncle Leo's radar screen yet. It'll be interesting to see if they really do care.
I'll make PM on Wed. After that, if DL ever denies me an upgrade to F, I'll simply take my full fare Y ticket and walk over to AA due to their superior coach seat pitch or NW due to their connect first fares. I'm certainly not going to sit in DL's steerage section given better choices.