thats a bit of an exageration, but it does contain a nugget of truth. There is definately a difference in analog cables between high end and cheaper products. analog cables are A/V cables like component or the red/white/yellow tv cables. on the other hand, digital cables are the same no matter the cost. a digital signal carries the same on a $150 dollar cable as a $5 cable. digital cables are HDMI or fiber optic audio cables
If you are asking about audio wire, it is not true. Single strand or solid wire would work in carrying the current to the various components of your system, but there are drawbacks. Wire for audio applications is comprised of a bundle of smaller wires. This supposedly gives the wire more surface area for the current to travel on but the main benefit is that it makes the wire substantially more flexible and easy to work with. It is also far less likely to break over time.