I wonder if Showcase Presents Superman did have an impact on sales and as a consequence the survey, if I remember correctly
the first Superman Showcase was priced low, printed on better paper stock and a best seller, few times reprinted.

Another point David and FFF statements that DC might make more money from a SA Archive then a color Showcase might have been true in the past,
but right now Archives are not selling, low cost formats are popular and DC is adapting to the market.
Basically nothing is written in stone, markets change, readers preferences change, price points come and go, looking back a $39.99 archive was cheap, in
few years a $59.99 archive would seem cheap.
I would not discount chronological TPBs at some future point just because DC could make more money from in in the past or because theme collections are
better sellers right now, corporations are out there to make money, I see no reason why DC would sit on all restored art other then right now it might not be
the right time for it.