Why haven't they...

[MacMillan of Rathdown]

From 1939 to December 1941 only those 3.5 million Britons and their other imperial allies such as Canada were involved in the war.

Those American films made during this period more often than not were concerned with life in occupied Europe-- Hollywood doing it's bit to convince the American public, which was largely isolationist, that there were good reasons to enter the war on the side of the French, Belgians, Dutch, Austrians, Norwegians, Danes, and yes, the British.

It (the war) didn't start when the US came in.

No, but it did end after the U.S. came in. (No doubt something to do with 16 million troops the US sent to fight in all theaters of the conflict.)

Hollywood has to remember that if a film is to be successful globally that inaccuracy will not go down as well overseas as it might do in the US.

I really think it all depends on whose ox is getting gored. I am sure many people in Britain were unhappy with the Mel Gibson film, The Patriot because of its portrayal of the British. Well, suprise, suprise, the picture made money in the UK, and did extremely well in -- India, where they may not exactly share your views regarding historical inaccuracy. I remember laughing my **** off listening to British film critics complaining that all of the main characters in the film Amadeus had American accents-- what did they expect? German accents? No, it was a case of British cinematic "chauvinism" because RADA-trained actors weren't cast in any of the principal roles.

Britain has a tiny film industry when compared to Hollywood. And Britain is pretty much unsurpassed when it comes to making "British" films. But, when it comes to making movies, Hollywood is the gold standard. Even if they sometimes take liberties with history.