I have a problem with the word post modernism  

To me, PM was, on the...
To me, PM was, on the whole, a false start in what was undoubtedly a necessary direction. It failed, and the default position was to resume the continuing "warming-up" of modernism, already underway when Michael Graves and Ettore Sottsass had their fun.
and tons of other great designers since these two...
This is a great statement by SDR especially the false start ........ It failed ... continuing warming up of modernism ...
It makes such good sence.

I suppose
the move was inevitable -- though one could perhaps trace the influence of Venturi's book to see HOW inevitable -- but it was (to me) an irrelevant and unnecessary distraction. Yet some of the result is worthy of attention, of course.
Schools, trends and movements are easy to over-estimate in terms of importance; after all, it's just a group of individuals who would be doing something worthy even in a vacuum.
In looking at the architectural work above, one can almost hear the gears working in the heads of the designers: "What can I add to what I was doing yesterday, before all this started, that won't totally freak out my esteemed peers but will still show that I'm on board with this new "freedom" ? Lets' see -- some textures -- but lets make them as geometric and controlled as possible. Some curves ? Ooh -- dangerous; let's make sure they're either arcs or circles, or else free form in plan (how did Corbu do it ?) so that the profiles in perspective will make nice safe verticals. Historic elements ? Okay. . .but have fun with them so NOBODY will think I've actually sold out to the classical crowd !"

Calling it a false start...
Calling it a false start probably only serves to confuse the term postmodernism even more, in much the same way the "post" of that word sends folks immediately and understandably in the wrong direction. Postmodernism was/is at once emergent and already part of the race, a story old as legs. Even if much of it seems like a slap to the face of modernism, a twist, a poke in the ribs, or as Koen so aptly put it, a spectacle, there is really nothing 'false' or 'start' about it. For better or worse, it's a part of the family of knowledge. One kid went to college, one kid went to a Grateful Dead concert, one kid... Heidegger, Eames, Derrida, Sottsass, you name them. Modernism, poststructuralism, whatever, all part of the stew.
One thing I'm not seeing addressed very much in this discussion is context. Postmodernism or, indeed, most any aesthetic that might have been tagged with the moniker of "Movement", as far as I can tell, has a tendency to often emerge as a kind of response, valid or not, to the potentiality of cultural totalitarianism. I am certainly simplifying this too much, but it should not be surprising that many of societies "isms" can be traced closely to periods of war or civil unrest. I believe this phenomenon can at least be pretty easily understood - if not found to be very acceptable - even in light of the fact that one of its manifestations is that it can make the tree lean rather sadly for some toward a state of moral relativism.
At worst, postmodernism - destructive to some notions as it might seem to be - simply adds something to a body of knowledge. That 'something' is sometimes referred to as enlightenment, but such definition is anybody's guess.
At its best, maybe it was saying, among other profanities, even though life is very serious, might it be good, at least at times, to not take certain things so seriously. As the kids like to say, or used to like to say - the term I'm reminded is already passe/postmodern - shit happens.

when i moved to NYC in the ...
when i moved to NYC in the late 70's looking for a place to live the term that i was hit with you want to live in a prewar apartment ?
I always thought that was a weird way to describe buildings. certain sections of the city are pre war it is just which war are we talking about