Is there a picture somewhere of the proposed 1992 or 1993 1500 pickup design
that Bob Lutz and Lee Iacocca had bad feeling for and rejected,
and ordered the designers to go do a “mini Kenworth T600” body style,
resulting in the 1994 pickup?

The initial '62s designed by Exner.... the "S-Body" or "S-design" platform would have been full-size, and very attractive. There was even a proposed large, wrap-around back window 2+2 coupe which probably influenced the Barracuda a few years later. The Imperial was sharp and exquisite in comparison to the bulbous, finned, awkward '59 - '63s that we got. The "S" Imperial was very modern and forward looking.

So a Ford F150 and a Dodge pickup had a child, and unfortunately the Ford genes came through. In profile that looks more like a F150 made for a foreign market than a Dodge at all. Good on Lutz and Iaccoca to ax that one. At least the Dodge Ram that resulted didn't look like everything else.

Manufacturers don't make money by not producing something they'd sell millions of.

Rolls-Royce, Bentley, Maybach, Ferrari, Maserati, Bugatti, Lamborghini, Mercedes-Benz AMG One, Aston Martin, etc., not high volume but they surely make big money on them. Quality or limited availability is another way to make money other than volume. I'm sure Dodge made money on the 3,300 Demons and so did the dealers, but as you say "some" manufacturers similar to Dodge could never survive selling Demon like cars alone and do have to have cookie cutter million-unit sales vehicles in order to pay the rent. Not so much with those exclusive type high end cars. Your statement is true to a big point but not completely.