I’ve read one author who’s not US born but does his homework so well, that for the first 3 books I did think he was a US novelist (he’s Irish).

Okay they are not magical books, but they have dealt with the supernatural and legends of the US, the different states, and history. He has really done his homework, and also visited the places, talked to people, which JK could well afford to do.

If an author comes off this badly writing outside his/her own country, it really is basic laziness, riding on success and hoping people won’t notice, and yes, a lack of imagination.