A few comments.
1. The AH may well still be in apparent good serviceable condition but the Project Team will be looking at supportability (availability of parts and cost) beyond the short term. In all aircraft types there comes a "tipping point" where the cost of ownership and obsolescence of critical components makes the case for upgrade compelling. The UK AH were unique in several ways, but also retained legacy parts from the US Army - in effect, the worse of both worlds from a supportability perspective. By aligning with the AH-64E program now, these risks and costs can be mitigated by certainty of supply (stand fast the concerns over "op sovereignty") and the lowest through-life costs by leveraging off the US Army's vast acquisition and support contracts. As an ex-RM, however, I will caution against the potential loss of independent capability as the AAC will now, largely, be left with an aircraft designed around US Army TTPs/SOPs. Some of our procedures will likely need to change. There is also the thorny issue over UK-offset; the WAH-64 was the "poster child" for paying over the odds to secure UK jobs. It seems that, in this case, only the support contract is up for grabs.
2. Mil vs Civ. Applicable across Defence, there is a drive to deliver savings whilst maintaining output - after all, how would people be judged for promotion if there wasn't? The problem that is building, however, is that this "bubble" has been built and sustained by a cadre of well trained people leaving the military with the necessary skills and qualifications. The "death spiral" occurs when, due to contractorisation, key skills are lost (e.g. Heavy Rects at Depth) and the outflow from an increasingly smaller military (which is why, after all, contractorisation exists...) reduces, and other, more lucrative, second careers are available (and many, under NEM, will not leave with an immediate Pension). Eventually you reach a point where the contractor has to bump up the pay and do the training; these costs are passed directly back to the military who, by this point, lack the skills, mass and resource to bring the job back "in house". This is the major issue I have with schemes such as MFTS and IOS - once you reach a certain point you cannot go back without a massive increase in cost and personnel.
3. Anything is ultimately supportable, if you have the money. Tornado will reach a point where the OTS spares are dwindling and the operators are forced to either change and qualify new components or resume the production of obsolete parts. Both are very expensive - I put a piece of DAS kit back into production once, and the manufacturers had to drag people out of retirement to tell them how to do it. Their comment was "it would have been easier to ask NASA to start building Saturn Vs again". The cost was eye-watering yet considered cheaper than buying, qualifying and declaring a newer system. The GAF can keep the GR going for some time yet, especially if they buy (a la USMC and GR9) a load of parts off us when ours go OSD.