Re:
as an amateur/hobbyist, even i find that single vague answer highly dubious. not attacking your suggestion by any means --- but is that really the accepted general consensus from the professionals on this forum/industry?
Not so much worst shape (which applies to most of the legacy a/c) but the planning intent.
The AV-8Bs were remanufactured with a new fuselage bet 1994 to 2001 for a service life of 20 years (or 6000 hours). The intent was to replace all AV-8Bs by 2021 and an IOC that would roughly coincide with the service life end of the earliest remanufactured AV-8Bs. As one can see, there is a bit of time to play around with with regards to USMC IOC.
In view of the program delays, USMC has reassessed its intent and likely now will require its AV-8Bs to operate til 2027 as the retirement date (with a potential upper limit of 2040 if required).
The problem is that because the original plan was to retire it by 2021, spare parts funding and industrial support beyond 2021 was not planned for. It could be worse with the retirement of the British harrier fleet as their industrial base prematurely terminates as well. Accordingly, maintaining it beyond 2021 would be an issue. At the same time, attrition losses affect AV-8B fleet at ~2 a year.
There is also a budget risk now (duplicating the UK) that the harrier fleet might be terminated early creating a capability gap but that only serves to create more pressure to hasten the IOC rather than explaining why the IOC was earlier in the first place.
The above is accurate as at July 2010 with some recent input from the UK budget cuts.