OnePlus' official store in North America ended sales of the OnePlus 5T a few weeks ago, citing a depletion of stock intended for the region. The company's web stores in Europe and India are also saying the same, which could be evidence of just how well the device has done commercially.
https://www.notebookcheck.net/The-OnePlus-5T-is-no-longer-available-in-Europe-and-India.298678.0.html