Yes, very old news indeed.
Thus did I say "you know what they did when they discovered CAT5..."
Full disclosure, I used a couple of much (
much) simpler CAT5 recipes for loudspeaker cabling for a year or two ca. 20 years ago myself.
I also used some enamel-insulated 18-ga single conductor magnet wire -- someone does actually sell such stuff as speaker cabling.
(I didn't buy them, though).
Award-Winning HiFi Audio Cables including bi wire speaker cable, solid core wire and stranded wire for loudspeakers. STARTING AT ONLY $12 PER FOOT!
anticables.com
I've never used any flat cables -- although I will note that way,
way back in the early days of massmarket hifi, even equipment manufacturers suggested the use of (flat) 300 ohm twinlead antenna cable (once the staple of VHF TV antenna hookups) for (short) runs that had to go under carpeting.