Douglas,Exactly!
You have pretty well covered all my points and there are only one or two things I would disagree with.
1. I disagree with your reading of the impact of impressionism. The initial reaction was shock/horror and genuine. To reduce it to the level of a marketing ploy is doing it a disservice. It changed the world.
2. Since I asked the original question I think it is only fair that I should attempt an answer. In the following I am aware that forever is a long time, it is unlikely that the human race will last forever and so it likely that one day painting will cease. The following answers assume everlasting life.
Do I think painting is dead? No.
Do I think painting will ever cease? No.
Do I think painting is dead as an artform? No.
Do I think painting as an artform will ever cease? No.
Do I think painting is dead as a valid and vital artform? Probably, although I am willing to accept that it might just be lingering on in intensive care.
Do I think painting will exist in the future as a valid and vital artform? No.
This is how I see the present and the future. I see a world where painting as an artform exists as a kind of endangered species. It still goes on and there are people out there (artists and artlovers) desperate to make sure that it always goes on. But it's not as a living, growing, healthy organism. It is an undeath at best.
I admit this is a bleak vision. Perhaps it represents my greatest fear since I have not yet given up hope of seeing a change in these shadows.