To the guy that asked about keeping jets in a flyable condition for later historical / museum / airshow circuit / BBMF type flying.
One of the main problems (apart from the obvious hours/cycles etc to keep an airworthy piece) is the physical cost of storing airworthy aircraft - whilst maintaining the airworthiness of it. The bean counters could do a cost / Vs benefit analysis and come up with a 'Negative' value added for the effort. Therefore it would be up to some 'private' concern - ala Vulcan team. I have seen at least a dozen airframes retired from the air forces that I have served in - and every one of the die hard aircrew ask exactly the same question - Why cant we store one to fly later?. Well unfortunately part of the reason to 'scrap the fleet' was cost cutting related, and therefore if you wanted to keep one flying - most of the cost cutting is lost. Simple economics really - and normally private consortiums struggle to fund such a project - let least make a profit for the effort.