For comparison, given the issues that the army is now facing with Challenger 2, obsolescence and a lack of an affordable upgrade path, I can't help thinking that being locked into someone else's upgrade path is a distinct advantage, rather than a disadvantage... we're very, very good at kicking cans along the road and letting design and manufacture capabilities die just to make year-ends balance, only to then have to pay fortunes to start from scratch when we really, really can't put things off any longer.