You make a very good point, and I would expect to see a high price on this type of car if it was manufactured.
But it is so difficult to see the HO people have nice things like this while we do without. If a frail little HO or even N gauge open autorack can be built, why not O ?
I don't have stats, but I know there's many of us HO'ers that avoid the 80' long cars like the plague.
Just as Sirt said: Too stinkin' long for the space most of us HO'ers have. Full sized racks and such take gigantic curves to look truly "good". Without huge curves they look very stilted and angular on curves and for me that really reduces my chances for "immersion". I also get a "two fer" deal with shorter cars: I can fit two 40' cars into the same space just one long car fills, thus making our truncated trains look longer.
Those that model "modern" are stuck trying to replicate in miniature the truly long equipment of today's railroading, and unless you have a gymnasium, the results often emphasize the caricature nature of model railroading.
However, there's no "wrong" way for one to enjoy their version of model railroading... so to each his own.
Me, I've tried racks and such in the dateless past, and didn't like the visuals... so I intentionally avoid such cars in my modeling now. (I even use the "condensed" Athearn heavyweight models for my two remaining passenger trains on my mythical Kansas City & Gulf railroad. The visuals of such cars are acceptable on my 24" and 22" main line curves... but just barely.)
Andre