XLR versus RCA

[Al ears]

Not only are these the cables used in production, they're also made to last. If they survive recording studio's and music venues, they'll survive every living room.

And that's the point, they don't get the same abuse in a hifi set-up so are unnecessary, also the reason many HiFi manufacturers don't go with the added expense of fitting them.

 

[manicm]

Here's my rule - if a component is truly balanced, and not piggy backing off the unbalanced topology, then use the balanced socketry.