PLovett
Your are correct, what the true charter companies have to do is re-equip with 15 year old equipment when our 30 year old equipment becomes too uneconomic to maintaintain. What I mean by "true charter companies" is those who are in business to try and make a profit from air charter as opposed to companies that attempt it, either a tax efficient vehicle, a play thing, or a means of subsidising the cost of owning a corporate plane.
One simple way of achieving this would be for the authorities not to allow an operator to mix private with public transport operations. It is just too convenient to say "Oh it was a private operation" when the crew did a 20 hour day or the runway just happens to be a tad short for for public transport. That crew who did the 20 hour day is tomorrows well rested public transport crew! No wonder that certain sections of our Industry have less than a bleamish free reputation. I think that applies to most countries. A few examples: The Challenger at Teterborough. Public Transport, but no one knew who the operator was! The G3 that crashed on the approach going to pick up G. Bush Snr. I think the combined age of the crew was over 130!