People HAVE to purchase the product, in alot of cases there is no other way
With certain products the government protects the people, i don't see why airline travel should be different than things like milk and beef, in a worldwide economy many many people depend on airline travel daily just to do their jobs, without the ability to fly to places like Europe and Hong Kong, a large portion of our businesses would suffer severely
You picked bad examples to illustrate your point, because it is almost exactly the same with milk and beef vs. travel. In each case there is a government agency that regulates the safety of the item.
But the government leaves it to the market place to sort out what grades of meat will be available and the demand and pricing for those grades of meat. In addition, the government doesn't (yet) require that you purchase any particular type, grade, or quantity of any foodstuff.
Same thing with the airlines - the government leaves it to the market place to decide the grades of service that will be available and the demand and pricing for those grades. The government also does not require that any person fly.
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This is a topic, by the way, on which the public has voiced it's opinions loudly and clearly. Over the years there have been airlines that have tried to provide a higher quality flying experience - more room in the seats, better food, etc, for an added price. They have all failed in the mass market. (There may be some niche carriers still operating that way.)
The traveling public has stated clearly that the main thing it wants is low fares. Given the choice between low fares + crummy service vs. higher fares + better service, the vast majority of the traveling public will select low fares + crummy service, and then voice their complaints about how crummy the service is.
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We have the situation that we have with airline roominess for the simple reason that every time an airline has tried to provide more room they haven't been able to attract enough people willing to pay for the extra room to make it viable.