I don't really blame people for taking advantage of these (I bought a couple myself), but your strawman is pretty absurb. You'd have to be living under a rock to not realize these were mistake fares.
...or someone who isn't an FTer, doesn't read the MR board, doesn't follow @DansDeals, or is looking at a route you haven't flown before and aren't familiar with the "right" price for, and not looking at enough different routes to see that there were freakishly low prices across the board.
I used to work for one of the big 4 air ticket dot-coms, and know from experience that airlines would occasionally slash prices on one route or another to boost load factors or poke their competitors in the eye.
I've flown between the east coast and Honolulu enough that yes, $100 each way from NYC-HNL is "oh $#!+, someone better be polishing their resume." To Pa Kettle, it's "pack yer bags, Maw, Delta done got us a Christmas sale!"
But that DTW-LAS you picked up for about $73? I'm with the Kettles on that. Never flown the route, and I know trips to casino cities tend to be cheap because you're going to lose your money there anyway - free motorcoach rides on the east coast, etc. So $73 from somewhere in the midwest to Vegas would not raise any red flags for me.
This does have me wondering whether all the times back in the day that EK wanted $800 for something everyone else wanted $2400 for were errors.
Sure they were published everywhere, but that's how the GDS works.
"Sure they were published everywhere" does, I remind you, equate to "You couldn't find anyone willing to take more of your money even if you wanted them to" if you happened to be booking an affected routing on Delta at that time.