Re: In-house
In the past the crown has been responsible for providing at least some its own armaments. As in the Royal Arsenal* and the Royal Naval Dockyard at Chatham.
That's only provisioning arms before a conflict that's now been handed over. When operational matters are outsourced there are additional risks. The refuelling fleet is only one aspect. F35 servicing is another. When day-to-day operational capacity is in the hands of private companies, not necessarily companies controlled by boards within the country, the ability of the militaries to get on with their job, as you put it, of killing people can be brought to a halt without their command structure or governments being able to do a thing about it.
* A late friend of mine was responsible for typesetting a book on that. He said they had a lot of trouble with the hyphenation.