They were the last two to retain an all-Pullman train (the Broadway Limited and the Panama Limited, respectively; the latter name was swapped for the CONO only after a popular song provided a marketing opportunity...the CONO was the second-tier train on that run IIRC). Whether those were primarily business or leisure travelers on the Panama Limited is a good question.I have read that, toward the end, New York–Chicago and Chicago–New Orleans were the two big long-distance markets for business travelers. Was this the case?
There was a third that held up fairly well, namely Southern's Crescent...while I think it trailed in third (remember, Atlanta was a lot smaller in the 60s), Southern kept it and a day train on that route (though the Piedmont Limited, the day train, stopped at Atlanta while the Crescent was tri-weekly past Birmingham) even post-Amtrak.
As to what I used to compare the Pullman fares to, I used the 1967 PRR fare table available at streamlinerschedules.com. There are two big things to remember with the old fare system from that era:
1) There really weren't buckets. Though a few roads (either CN or CP were among the first) were able to vary fares a bit based on seasonal demand towards the end, there was no concept of revenue management. Not only weren't there good systems to handle it, but I don't think the ICC was willing to be that flexible.
2) A lot more of the fare was "swallowed up" in the coach charge. Even with this in mind, please consider that in all of these cases I'm going off of the parlor car railroad fare (the base coach fare is usually lower) plus the room charges. Also, a lot of this was structural (the room charges went to a separate entity, Pullman, and the railroad still needed a chunk of the cost to cover running the train). However, if you look at the Penn Central fare tables from '71 on the NEC, note how little variation there is between the Metroliner Metroclub seats and the "regular" trains' coach fares:
One-way Fares, NYP-WAS:
Coach: $13.00
Parlor Car: $23.40 ($20.25 fare plus $3.15 accom. charge; $3.15 more for a drawing room)
Metroliner Coach: $17.00
Metroclub: $27.40
-Worth noting (and someone else picked up on this) is that if you doubled coach fares but kept the sleeper fares alone (and didn't lose business in the process), a lot of the LD trains would be somewhere around break-even. This would also be reasonably close to the older fare structure. In some cases, you could also make a substantial dent in things if you were able to hike the room charges and add rooms.
Finally, with minimum wage, not only is that a result of a political process, but the minimum wage has varied in what it can buy/what it is worth dramatically over time. I list multiple measures because I don't trust one measure to be perfect...for example, the CPI has been massively affected by the housing situation over the last few years.
(A closing note that just came to mind: I realized that, having real perspective on a lot of this, I'm generally less inclined to grumble about expensive fares. Add-on fees, yes, but not fares so much.)