Has biwire speaker cabling become "old" ?

I have bi-wired every speaker that I've owned that could be bi-wired, but never heard any difference in sound. Bi- amplifying is the only way I heard a difference. Just try it both ways and see (hear) what you like best.

For short distances within home audio applications and audio-signal it doesn't matter. I used single wire-run threaded through both upper and lower binding posts instead of jumper, now I have bulk Kimber 4tc where 3x3 wires are hooked up to bottom binding posts and 2x2 wires hooked up at upper binding posts and it doesn't matter simply due to very small degree of magnitude to be somehow noticable.
Not sure if I hear any difference between types of connection when length of speaker wire is increased by 10x per each speaker.

In terms of the initial question, I have not noticed that there are less biwire speakers, but that cable companies are offering less internally biwired cables in favor of double runs or jumpers, though many cables are easy to reterminate to be internally biwired. so maybe internally biwired cables are currently out of favor...

"03-19-15: Polk432
I have bi-wired every speaker that I've owned that could be bi-wired, but never heard any difference in sound. Bi- amplifying is the only way I heard a difference. Just try it both ways and see (hear) what you like best."

I do hear the difference in biwiring most of the time, and now that I use just Vandersteens, its 100% of the time. Its a big difference. But if you don't hear the difference, why waste the extra money on getting biwire cables?

I'm with Z on that one. It usually is keeping the skin effect off the lower end cables and many other things that cables deal with. I was only able to afford a pair of AQ Castle Rock bi wired, but I've heard the same speakers I own with TWO separate runs of the same cable in the same system and HOLY COW is there a difference. It wasn't slight to me either. Anytime you can keep signals separate it's usually a good things. The signals are different on each run and it's night to keep them away from each other if you can. Higher resolution systems will shows the differences most of the time.