747forever
You seem to be ignoring the effects of competition and the desires of the paying passengers.
For example, if you put your 747 in a market strong enough to support 2 flights a day profitably. So, along comes a competitor willing to commit 2 767s and a 757 to the route against you. With 2 planes, you can only offer a morning and mid-day flight, your competitor puts the 767 against your two flights and offers a late day to catch premium business travelers who want to fly at the end of the business day--you're in trouble.
This is essentially what drove the 747 off the Atlantic market. It became a 767 market, with 777s on the highest volume routes--primarily LON. By using smaller planes, the airlines could offer non-stop flights connecting more smaller cities in Europe and North America. 747s were common sights on the tracks in the '80s, rare now. Tokyo was 747 Central a decade ago, now they are out-populated by 777s. A glance out the concourse at Narita last month, showed more B777s and A330s than B747s. Purely, anecdotal, but not unusual. A 747 at PHNL is rare now, but in 89 very common.
A long way of saying, the travel market is getting more fractionalized toward non-stop flights connecting smaller and smaller markets. They have delivered over 900 B777s while they delivered maybe half that number of B747s and the trend lines are going in opposite directions.
GF