Nailed it. Noctua, please take note;
No matter how great/well your fans perform, the color scheme is a deal-breaker! It does not matter if you're proud of it, most people aren't. I will never put one of those "ugly-as-jankys-mama" fans in my cases, nor cases I build for clients/customers. There are plenty of excellent performing, better looking fans out there. You don't have a corner on the market. Light grey and dark grey would be infinitely better! Would it kill ya? Seriously..
I understand your logic and i'm sure Noctua does too: it seems they just consider the brand recognition more important.
Personally, i don't give a crap if the fans are brown, white, blue, pink, with triangles, with squares, whatever: i'm interested in the performance,
and most of all, the noise. In these two metrics, Noctua is among the very best there is.
Pricey, for sure, but quality is expensive.
There are those that care more for the aesthetics of the fans then of their performance. I wouldn't be surprised if there are more people in this "category" then there are in the "category" that i'm in but
it seems Noctua sees things with my perspective.
If you spread out like 30 or so different fans from several brands, including Noctua and place them on a table with the brand's name covered, pretty much every person that has @ least some knowledge of fans can identify a Noctua fan,
even from several feet away. It will
probably be more difficult to identify the other ones, even standing right next to the table.