All Boeing aircraft can go beyond the published limit, IF someone wants to pay for the increased maintenance requirements. Usually this is not economically feasible. One thing I have learned in 45 years of aircraft maintenance and operations, never say never and never say always.
AS the LOV on B767 is 75,000 cycles and 150,000 Hours, that is not usually a factor. It is true however that as the aircraft gets older, more maintenance is needed and required.
Pricing is more affected by engine condition, aircraft age, flight hours and flight cycles than by heritage. Aircraft records can also be a significant factor on pricing. I have never heard of someone paying a premium based on heritage.
Corporate welfare is never a good idea. Airlines have always been a boom and bust industry and to get them used to living on money borrowed from China, for our grandkids to pay back, is a bad precedent.
Actually, what needs to happen is the airlines need to be broken apart so they are not too big to fail. The problem is we have put all of our eggs in one basket.
Airlines are businesses just like any other and need to learn to survive on their own. It is not up to the taxpayer to provide support for any business. The policy of too big to fail is a failed policy. If a business is too big to fail then they fall into a monopoly category and should be broken down.