The OnePlus Nord 2 is not a failure. It was released to much fanfare and was well-received by critics. However, it did not sell as well as OnePlus had hoped, and was discontinued after just six months.
There are a number of reasons why the OnePlus Nord 2 did not sell as well as its predecessor. One reason is that it was released at a time when there was a lot of competition in the mid-range smartphone market. Another reason is that it was more expensive than the original OnePlus Nord, which was released at a time when there was less competition in the market.
The OnePlus Nord 2 is not a failure, but it was not as successful as OnePlus had hoped.