Age Limit for Speaker Cables

I have a 8' pair of XLR Series 5 reference speaker cables purchased new in 1997. No oxidation or cracking found in the cables and everything seems fine. Throughout the years I've upgraded all other components (many times) and cables except these. My other equipment is currently under 2 years old.
My budget is $1000 and am wondering if today's cables are that much more improved than in 1997. Can I find a better, more transparent, accurate, musical sounding cable for less than what I paid during the Clinton presidency? Much less?
Thanks and happy listening