Somehow I feel like GIMP's lack of popularity has more to do with its reputation for having a horrendous and impenetrable interface than its name.
At one point in the recent past there was a fork of GIMP named "Glimpse," yet weren't a sudden influx of users who were waiting for a more polite name.
BUT, lack of users might just be that it's too late, now. People use web-based tools like Figma, I wouldn't think a lot of people are looking for a Photoshop alternative.
Krita is doing just fine. It has the subjectively "better" name, but also the improved UX.
We're missing the last part of this quadrant with a Krita-like app that has great UX but a bad name, but the preponderance of the evidence thus far tells me that it is more likely than not that the name didn't matter, or at the very least that the UX definitely did matter while the name might not have.
At one point in the recent past there was a fork of GIMP named "Glimpse," yet weren't a sudden influx of users who were waiting for a more polite name.