Where the RN is concerned, the Brits have profited far more from the so-called 'special relationship' than the US. From my attendance at various bilateral meetings, I know how much research and technological know-how we have received and how we have been special beneficiaries of exclusive intelligence and other sensitive information. Sometimes it's meant freebie equipment, use of trials ranges, monitoring and training facilities too so don't knock it.
With us being so reliant on US firepower, e.g. CAS, artillery support, transport and infantry back-up for our troops in Iraq and Afghanistan, we shouldn't be taking it for granted that they'll always be there to bale us out in any future conflict. I keep hearing that we'll never go it alone without Yank help. Heaven help us if, one day, it's not there when we need it. God (and Uncle Sam) only helps those who help themselves so, in my opinion, they have every right to be concerned if we leave them to pick up even more of the burden than they are already carrying.