Yeah it's steep. But. It's also just a pc. Many ppl have no desires at all for bling, rgb, uber neat wiring, color matching, themes etc. Some ppl are the opposite, and thats what you'll see at shows, on advertising etc, the ultimate bling where looks are more important than performance.
Most ppl fall in between, they like a little bling, but also want decent performance, so compromise is a necessity. In your case, you have a particular desire for the perfect look for the cables, so the price is what it is. If you don't want to pay that much, you'll have to compromise.
I didn't want to pay over $200 for my case, but I wanted that particular case, there were no substitutes that would accomplish my goals or satisfy my aesthetics demands, so I paid the price. But then again, there's less than a handful of ppl on the planet with 2x 240mm rads and a full custom loop inside a mITX case with only 12.7L, most mITX are @ 20L and still won't fit that loop.