why do companies charge double for xlr cables?

For some cables whether you buy XLR or RCA , there is a small premium for XLR which is fine. But in many cases I've seen (ie. Audience for example) the XLR version cost double what the RCA version costs , just wondering why.

Is it true then , just as in electronics, that just because you have XLR connection that is still may not be fully balanced?