Speaker cables are literally balanced, unless you're grounding them at the speaker. I grant you that if you're grounding them at the amp it's 'fake balanced', but if you're running an amp with an output transformer then it's literally balanced.
Also arguably you only need balanced when the noise gets way too much. When driving a speaker the power audio signal is much much much higher than any noise being picked up over a reasonable length.
For lengths longer than that, balanced cables (or digital signals over Ethernet) are used and the speaker has more local amplification.
