It makes you understand why the oft-questioned "Why don't Ryanair/Easyjet/etc get into long haul" doesn't happen; because they understand the market only too well.
Get into a plane London-Hong Kong (or other trunk routes), note how they are full every trip you make, and think, like Yosser Hughes, "I can do this". But by no means all on board have just gone out and bought a simple trip London to Hong Kong. Many are connecting with affiliated carriers. Some are keen to build up their OneWorld miles elsewhere. Quite a number are on long-standing corporate world wide arrangements. Those at low fares only make up residual revenue at the end of this process. Underneath the floor the freight and mail is similarly hard-won over years.
This is not to say we should meekly accept the status quo. But being an airline entrepreneur is a complex affair, and jumping straight into a high-cost business is best done in sensible stages, as all those who have succeeded in this area have done.