F-35 pilot held 50-minute airborne conference call with engineers before crash

Who eats the loss under such circumstances?

Government or Lockheed Martin or are these 200 million dollar jets insured ?

Ultimately the US taxpayers will eat the loss in either case. If the government tried to charge it back to Lockheed Martin they'd just raise the price on subsequent programs to compensate.

The government does insure weapons of war. Who would write the policy?

Usually wars, vis major are exceptions in insurance policies.