I'm sorry for writing inexplicit.
What I meant e.g.:
Air Travel Boom: Los Angeles International to London Heathrow (and reverse). There is a demand of ~4000 pax a day.
My airline offers four flights a week with 302 pax each.
The plane is a not too old DC-10-30 in good condition and the prices were -15% (now -20%) from standard prices.
Due to the game is new, my CI is ~20 and RI is ~45 (and I spent a good part of my profit in marketing).
Maybe 2000 of these 4000 Pax think "Oh no, new airline, I won't visit my family in Los Angeles" or anything like this. But out of 4000 there must be 302 people who think "I don't like this airline, I have DC-10 and I won't pay one Dollar to fly there, but I must fly there because my boss told me/I have to visit my dad for spend him a kidney/whatever".
I can understand your tweaks and the results if there is competition. If there are 10 airlines and 8 are good and two are bad, it's normally pax choose the better airlines. But without competition, they have no choice, also if they hate everything about this one and only airline.
It's not true that long-haul planes can't make a profit without good C/F demand! In the previous game worlds I've even had very profitable A340s flying in standard all economy seating for flights longer than 5000nm.
You're right, but at this stage of the game most aircraft are not the newest and efficient ones.