Curtain rods are a solved problem with widespread availability across the quality spectrum, this is a total non-issue.
Curtain rods are a solved problem with widespread availability across the quality spectrum, this is a total non-issue.
I think the details matter. Curtain rods are typically 1-4" from the wall. This product looks like it works best <0.5" [0] from the wall otherwise it's possible the hanger will move around or have a "sagging" look.
Finding curtain rods that are that close is uncommon and limited in styles/options (I didn't see one on a quick amazon/aliexpress search). That's not to say you're wrong, but I don't think it's as simple as you believe it to be.
[0] https://ksr-ugc.imgix.net/assets/043/060/840/f8e1ace8b30ae8b...
Do an Image Search for "Clothes Railing U Bracket" for example.
But I agree you could build/attach small sidewalls or simply blocks and use this u bracket. But we've entered DIY space since it's not a common package and "readily available" as a solved problem.