there'd be a number of A330 Tankers for sale for crab to coveniently buy...
There would be two actually, one of which is still under conversion. If they then had to go through the procurement loop to buy and convert the remainder, the Tristars and 10s could find themselves lasting even longer....
But even if we went down that route, the MOD doesn't have the money to buy them up front.
Anyway, agreed that it is costly but people forget that it's not just about buying the aircraft. It's a complete package, and includes all the infrastructure and associated costs, even down to the cost of providing toilet rolls for 27 years. There are lots of hidden costs that people don't appreciate. Foe example, the aircraft may be deployed away from base so the crew have to be accommodated etc. AirTanker personnel would probably expect Ts & Cs that include a pension. Someone has to pay for all these things. Its all factored into the price. The real world is expensive.
Whether AirTanker will make excessive profits is another matter and there should have been levels agreed within the contract. If there weren't, perhaps that's a bigger scandal.