I have heard the Hi Fidelity interconnects in a few different systems now. So systems sounded much better and some where the improvement was not that pronounced. Don't know the model or level and the pricing of them. There is so much that goes into what makes a system improve and why. All that matters is if you hear a benefit in your system. As for the high pricing of audio cables/tweaks/components, etc., go make your own and see what the actual cost is to not only purchase materials, but have someone who will sell you small quantities of materials to start out, then design an appealing design, probably need someone to do a CAD drawing, market that out to manufacturers who will make you what you need in small quantities, design a shipping container with wrapping, foam inserts, etc., add shipping, expense, get a website, pictures of your items, specs, answer countless email questions, add tax you will pay to Uncle Sam after you move form selling them out of your garage or kitchen table, going to a show paying for a room, paying for reviews, what else did I miss, well you get the idea. I do agree that the prices can be very high but every one has their own budget and what they will pay for an item if they feel their system shows enough improvement.
Happy Listening.