Better cables won't sound worse, they might reveal more of the shortcomings of lesser equipment though!
I had AudioQuest Emerald for several years. I was given the chance to audition a pair of Purist Colossus while I was using the Emerald. After a couple of days I determined that I would buy the Purist cable no matter how much they cost because they were so much better. When I learned the 1m pair cost $1200 I sent them back to the store. That happened a little more than ten years ago, since then I have replaced all of my cables with Purist. Their prices have come down and my spending ability has risen a little.
Their newer cables have come down in price from where the older models were priced, but in my experience they are better than all but the top-of-the-line Dominus.
I auditioned a pair of the Dominus ICs loaned by a friend from AudiogoN. They cost over $7000 so there was no way I could afford them, even as a used cable, but they sounded so good I could not believe it. I have never heard anything that caused such a great improvement in my own system. Even the purchase of a much better amp did not provide as great an improvement in the sound!
I went from a Emerald IC/Black speaker cable wired system to all Purist and the improvement was worth the cost. The new stuff simply sounds better.