We don't really have a good baseline for this, but I don't think this is right. I think it is true that Trump is sort of a quasi incumbent, but I don't think it is an abysmal performance.
Haley's best performance was New Hampshire where a significant chunk of Democratic leaning independents voted for her.
She did terrible in Iowa even with Trump's support diluted by DeSantis and Ramaswamy.
She lost to "none of these candidates" in Nevada.
South Carolina was her home state and also had some Democratic leaning voters voting for her. She did worse than New Hampshire.
She got obliterated in Michigan which was an open primary.
The rest of the contests are a lot more like her showing in Michigan. She could lose these primaries by 50-70 points. That's been close to what the "Never Trump" polling has been like in the party.
In the general election most of those people come home to Trump rather than voting for the Democrat.
IDK. I feel like people are overinterpretating a handful of odd early primary contests. And re: the primary polling, Trump's polling has been pretty typical of presidential primary polling error. Primary polling has very large polling error compared to general election polling. It is inherently fairly noisy.
If later contests go much better for Haley I might revise this, but I don't really think this is evidence of a major weakness for Trump. We certainly haven't seen evidence in the general election polls to that effect either.